View source for Measles

{{Short description|Viral disease affecting humans}}
{{About|the disease}}
{{Distinguish|text=either [[rubella]] (sometimes called "German measles") or [[roseola]], other viral diseases that cause a rash and fever}}
{{protection padlock|small=yes}}
{{Use dmy dates|date=May 2025}}
{{cs1 config|name-list-style=vanc|display-authors=6}}
{{Infobox medical condition
| name = Measles
| image = RougeoleDP.jpg
| alt = 
| caption = A child showing a day-four measles rash
| field = [[Infectious disease (medical specialty)|Infectious disease]]
| synonyms = Morbilli, rubeola, red measles, English measles<ref name=Mil2015/><ref name=Stan2002>{{cite book|last=Stanley|first=Jacqueline|title=Essentials of Immunology & Serology|year=2002|publisher=Cengage Learning|isbn=978-0-7668-1064-8 | pages = 323|url=https://books.google.com/books?id=nuCT5RVToN4C&pg=PA323|url-status=live|archive-url=https://web.archive.org/web/20170908140851/https://books.google.com/books?id=nuCT5RVToN4C&pg=PA323|archive-date=8 September 2017}}</ref>
| symptoms = Fever, cough, runny nose, red eyes, rash<ref name="Merck Manual" /><ref name=CDC2014SS/>
| complications = [[Pneumonia]], [[seizure]]s, [[encephalitis]], [[subacute sclerosing panencephalitis]], [[immunosuppression]], hearing loss, blindness<ref name="Pink Book" /><ref name=Rot2016/>
| onset = 10–12 days after exposure<ref name="WHO2014"/><ref name="Conn2014">{{cite book|last1=Bope|first1=Edward T.|url=https://books.google.com/books?id=Hv8fBQAAQBAJ&pg=PT189|title=Conn's Current Therapy 2015|last2=Kellerman|first2=Rick D.|date=2014|publisher=Elsevier Health Sciences|isbn=978-0-323-31956-0|pages=153|archive-url=https://web.archive.org/web/20170908140851/https://books.google.com/books?id=Hv8fBQAAQBAJ&pg=PT189|archive-date=8 September 2017|url-status=live}}</ref>
| duration = 7–10 days<ref name=WHO2014/><ref name=Conn2014/>(not including complications)
| causes = [[Measles virus]]<ref name="Merck Manual" />
| risks = 
| diagnosis = 
| differential = 
| prevention = [[Measles vaccine]]<ref name=WHO2014/>
| treatment = [[supportive treatment|Supportive care]]<ref name=WHO2014/>
| medication = 
| frequency = 20 million per year<ref name="Merck Manual" />
| deaths = 140,000+ (2018)<ref name="who._More">{{cite press release | title = More than 140,000 die from measles as cases surge worldwide | work = [[World Health Organization]] (WHO)| date = 5 December 2019| access-date = 4 September 2020| url = https://www.who.int/news-room/detail/05-12-2019-more-than-140-000-die-from-measles-as-cases-surge-worldwide| archive-date = 6 August 2020| archive-url = https://web.archive.org/web/20200806185302/https://www.who.int/news-room/detail/05-12-2019-more-than-140-000-die-from-measles-as-cases-surge-worldwide| url-status = live}}</ref><ref name="cdc._Glob">{{cite web| title = Global Measles Outbreaks| work = U.S. [[Centers for Disease Control and Prevention]] (CDC)| date = 17 August 2020| access-date = 4 September 2020| url = https://www.cdc.gov/globalhealth/measles/globalmeaslesoutbreaks.htm| archive-date = 7 September 2020| archive-url = https://web.archive.org/web/20200907110447/https://www.cdc.gov/globalhealth/measles/globalmeaslesoutbreaks.htm| url-status = dead}}</ref>
}}

'''Measles''' (probably from [[Middle Dutch]] or [[Middle High German]] ''masel(e)'', meaning "blemish, [[blood blister]]")<ref>{{Cite web
|url=https://www.etymonline.com/word/measles#etymonline_v_12498
|title=measles (n.)
|website=[[Online Etymology Dictionary]]
|author=Douglas Harper
|access-date=14 September 2024
|publisher=
|date=n.d.
|archive-date=14 September 2024
|archive-url=https://web.archive.org/web/20240914041845/https://www.etymonline.com/word/measles#etymonline_v_12498
|url-status=live
}}</ref><ref>{{Cite web |title=measles |url=https://www.oed.com/dictionary/measles_n |archive-url=https://web.archive.org/web/20230920035137/https://www.oed.com/dictionary/measles_n |archive-date=20 September 2023 |access-date=10 April 2025 |website=Oxford English Dictionary |url-status=live }}</ref> is a highly contagious, [[Vaccine-preventable diseases|vaccine-preventable]] [[infectious disease]] caused by [[Measles morbillivirus|measles virus]].<ref name="Merck Manual">{{cite web |last=Tesini |first=Brenda L. |date=July 2023 |editor= |title=Measles |url=https://www.merckmanuals.com/professional/pediatrics/common-viral-infections-in-infants-and-children/measles |website=Merck Manual Professional |access-date=10 April 2025 |archive-date=8 April 2025 |archive-url=https://web.archive.org/web/20250408184735/https://www.merckmanuals.com/professional/pediatrics/common-viral-infections-in-infants-and-children/measles |url-status=live }}</ref><ref name="Pink Book" /> Other names include ''morbilli'', ''rubeola'', ''9-day measles, red measles'', and ''English measles''.<ref name=Mil2015>{{cite book|last=Milner|first=Danny A.|title=Diagnostic Pathology: Infectious Diseases E-Book|year=2015|publisher=Elsevier Health Sciences|isbn=978-0-323-40037-4 | pages = 24|url=https://books.google.com/books?id=YJ_uCQAAQBAJ&pg=PA24|url-status=live|archive-url=https://web.archive.org/web/20170908140851/https://books.google.com/books?id=YJ_uCQAAQBAJ&pg=PA24|archive-date=8 September 2017}}</ref><ref name="Merck Manual" />

Symptoms usually develop 10–12 days after exposure to an infected person and last 7–10 days.<ref name="WHO2014">{{cite web|date=14 November 2024|title=Measles Fact Sheet|url=https://www.who.int/en/news-room/fact-sheets/detail/measles|access-date=10 April 2025|website=[[World Health Organization]] (WHO)|archive-date=28 November 2022|archive-url=https://web.archive.org/web/20221128010546/https://www.who.int/en/news-room/fact-sheets/detail/measles|url-status=live}}</ref> Initial symptoms typically include [[fever]], often greater than {{cvt|40|C|0}}, cough, [[Rhinitis|runny nose]], and [[conjunctivitis|inflamed eyes]].<ref name="Merck Manual" /><ref name=CDC2014SS/> Small white spots known as [[Koplik's spots|Koplik spots]] may form inside the mouth two or three days after the start of symptoms.<ref name=CDC2014SS/> A red, flat rash which usually starts on the face and then spreads to the rest of the body typically begins three to five days after the start of symptoms.<ref name="CDC2014SS">{{cite web|date=3 November 2014|title=Measles (Rubeola) Signs and Symptoms|url=https://www.cdc.gov/measles/about/signs-symptoms.html|url-status=dead|archive-url=https://web.archive.org/web/20150202192809/http://www.cdc.gov/measles/about/signs-symptoms.html|archive-date=2 February 2015|access-date=5 February 2015|website=U.S. [[Centers for Disease Control and Prevention]] (CDC)}}</ref> Common complications include [[diarrhea]] (in 8% of cases), [[Otitis media|middle ear infection]] (7%), and [[pneumonia]] (6%).<ref name="Pink Book" /> These occur in part due to measles-induced [[immunosuppression]].<ref name=Rot2016>{{cite journal | vauthors = Rota PA, Moss WJ, Takeda M, de Swart RL, Thompson KM, Goodson JL | title = Measles | journal = Nature Reviews. Disease Primers | volume = 2 | pages = 16049 | date = July 2016 | pmid = 27411684 | doi = 10.1038/nrdp.2016.49 | doi-access = free | title-link = doi }}</ref> Less commonly, [[seizure]]s, [[blindness]], or [[encephalitis|inflammation of the brain]] may occur.<ref name="Pink Book" /><ref name=WHO2014/>

Measles is an [[airborne disease]] which [[Human-to-human transmission|spreads easily from one person to the next]] through the [[cough]]s and [[sneeze]]s of infected people.<ref name=WHO2014/> It may also be spread through direct contact with mouth or [[mucus|nasal secretions]].<ref name="WHO2014" /> It is extremely contagious: nine out of ten people who are not immune and share living space with an infected person will be infected. Furthermore, measles's [[reproductive number]] estimates vary beyond the frequently cited range of 12 to 18,<ref>{{Cite journal|last1=Guerra|first1=Fiona M.|last2=Bolotin|first2=Shelly|last3=Lim|first3=Gillian|last4=Heffernan|first4=Jane|last5=Deeks|first5=Shelley L.|last6=Li|first6=Ye|last7=Crowcroft|first7=Natasha S.|date=December 2017|title=The basic reproduction number (R0) of measles: a systematic review|journal=The Lancet. Infectious Diseases|volume=17|issue=12|pages=e420–e428|doi=10.1016/S1473-3099(17)30307-9|issn=1474-4457|pmid=28757186 }}</ref> with a 2017 review giving a range of 3.7 to 203.3.<ref>{{cite journal | title = Complexity of the Basic Reproduction Number (R0) | year = 2019 | publisher = NIH website | pmc = 6302597 | quote = [a] review in 2017 identified feasible measles R0 values of 3.7–203.3 | last1 = Delamater | first1 = P. L. | last2 = Street | first2 = E. J. | last3 = Leslie | first3 = T. F. | last4 = Yang | first4 = Y. T. | last5 = Jacobsen | first5 = K. H. | journal = Emerging Infectious Diseases | volume = 25 | issue = 1 | pages = 1–4 | doi = 10.3201/eid2501.171901 | pmid = 30560777 }}</ref> People are infectious to others from four days before to four days after the start of the rash.<ref name="Pink Book" /> While often regarded as a childhood illness, it can affect people of any age.<ref name=Medscape2018>{{cite report |last1=Selina|first1=SP|last2=Chen|first2=MD|date=6 June 2019 |title=Measles |url=https://emedicine.medscape.com/article/966220-overview |url-access=registration|publisher=Medscape |url-status=live|archive-url=https://web.archive.org/web/20110925023230/http://emedicine.medscape.com/article/966220-overview |archive-date=25 September 2011 }}</ref> Most people do not get the disease more than once.<ref name=WHO2014/> Testing for the measles virus in suspected cases is important for public health efforts.<ref name="Pink Book" /> Measles is not known to occur in other animals.<ref name="WHO Measles fact sheet" />

Once a person has become infected, no specific treatment is available, although [[supportive care]] may improve outcomes.<ref name=WHO2014/> Such care may include [[oral rehydration solution]] (slightly sweet and salty fluids), healthy food, and medications to control the fever.<ref name=WHO2014/><ref name="Conn2014"/> [[Antibiotics]] should be prescribed if secondary bacterial infections such as ear infections or pneumonia occur.<ref name=WHO2014/><ref name="WHO Measles fact sheet" /> [[Vitamin A]] supplementation is also recommended for children under the age of 5.<ref name="WHO2014" /> Among cases reported in the U.S. between 1985 and 1992, death occurred in 0.2% of cases,<ref name="Pink Book" /> but may be up to 10% in people with [[malnutrition]].<ref name=WHO2014/> Most of those who die from the infection are less than five years old.<ref name="WHO2014" />

The [[measles vaccine]] is effective at preventing the disease, is exceptionally safe, and is often delivered [[MMR vaccine|in combination]] with other vaccines.<ref name=WHO2014/><ref name="Russell2019">{{cite journal |last1=Russell |first1=SJ |last2=Babovic-Vuksanovic |first2=D |last3=Bexon |first3=A |last4=Cattaneo |first4=R |last5=Dingli |first5=D |last6=Dispenzieri |first6=A |last7=Deyle |first7=DR |last8=Federspiel |first8=MJ |last9=Fielding |first9=A |last10=Galanis |first10=E |title=Oncolytic Measles Virotherapy and Opposition to Measles Vaccination. |journal=Mayo Clinic Proceedings |date=September 2019 |volume=94 |issue=9 |pages=1834–39 |doi=10.1016/j.mayocp.2019.05.006 |pmid=31235278|pmc=6800178 }}</ref> Due to the ease with which measles is transmitted from person to person in a community, more than 95% of the community must be vaccinated in order to achieve [[herd immunity]].<ref name="Ludlow2015">{{cite journal |vauthors=Ludlow M, McQuaid S, Milner D, de Swart RL, Duprex WP |date=January 2015 |title=Pathological consequences of systemic measles virus infection |journal=The Journal of Pathology |volume=235 |issue=2 |pages=253–65 |doi=10.1002/path.4457 |pmid=25294240 | doi-access = free | title-link = doi }}</ref>{{Better source needed|reason=The current source is insufficiently reliable ([[WP:NOTRS]]).|date=April 2025}} [[Vaccination]] resulted in an 80% decrease in deaths from measles between 2000 and 2017, with about 85% of children worldwide having received their first dose as of 2017.<ref name="WHO2014" /> Measles affects about 20 million people a year,<ref name="Merck Manual" /> primarily in the developing areas of Africa and Asia.<ref name=WHO2014/> It is one of the leading vaccine-preventable disease causes of death.<ref name=Kabra2013>{{cite journal | vauthors = Kabra SK, Lodha R | title = Antibiotics for preventing complications in children with measles | journal = The Cochrane Database of Systematic Reviews | volume = 2013 | issue = 8 | pages = CD001477 | date = August 2013 | pmid = 23943263 | doi = 10.1002/14651858.CD001477.pub4 | pmc = 7055587 }}</ref><ref>{{cite web |title=Despite the availability of a safe, effective and inexpensive vaccine for more than 40 years, measles remains a leading vaccine-preventable cause of childhood deaths. |url=https://www.who.int/immunization/newsroom/MI_Fact%20Sheet_17_jan_2007.pdf |access-date=16 February 2019 |archive-date=12 December 2019 |archive-url=https://web.archive.org/web/20191212171454/https://www.who.int/immunization/newsroom/MI_Fact%20Sheet_17_jan_2007.pdf |url-status=dead }}</ref> In 1980, 2.6 million people died from measles,<ref name=WHO2014/> and in 1990, 545,000 died due to the disease; by 2014, global vaccination programs had reduced the number of deaths from measles to 73,000.<ref name=GBD2015De>{{cite journal | vauthors = ((GBD 2015 Mortality and Causes of Death Collaborators)) | title = Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980-2015: a systematic analysis for the Global Burden of Disease Study 2015 | journal = Lancet | volume = 388 | issue = 10053 | pages = 1459–1544 | date = October 2016 | pmid = 27733281 | pmc = 5388903 | doi = 10.1016/S0140-6736(16)31012-1 }}</ref><ref name=GDB2013>{{cite journal | title = Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013 | journal = Lancet | volume = 385 | issue = 9963 | pages = 117–71 | date = January 2015 | pmid = 25530442 | pmc = 4340604 | doi = 10.1016/S0140-6736(14)61682-2 | vauthors = ((GBD 2013 Mortality Causes of Death Collaborators)) }}</ref> Despite these trends, rates of disease and deaths increased from 2017 to 2019 due to a decrease in immunization.<ref>{{cite web |title=Measles cases spike globally due to gaps in vaccination coverage |url=https://www.who.int/news-room/detail/29-11-2018-measles-cases-spike-globally-due-to-gaps-in-vaccination-coverage |website=[[World Health Organization]] (WHO) |access-date=21 December 2018 |date=29 November 2018 |archive-date=24 December 2018 |archive-url=https://web.archive.org/web/20181224020216/https://www.who.int/news-room/detail/29-11-2018-measles-cases-spike-globally-due-to-gaps-in-vaccination-coverage |url-status=live }}</ref><ref>{{cite news |title=U.S. measles cases surge nearly 20 percent in early April, CDC says |url=https://www.reuters.com/article/us-usa-measles/measles-cases-in-u-s-surge-nearly-20-in-early-april-cdc-says-idUSKCN1RR1H4 |access-date=16 April 2019 |work=Reuters |date=16 April 2019 |archive-date=15 April 2019 |archive-url=https://web.archive.org/web/20190415160142/https://www.reuters.com/article/us-usa-measles/measles-cases-in-u-s-surge-nearly-20-in-early-april-cdc-says-idUSKCN1RR1H4 |url-status=live }}</ref><ref>{{cite web |title=Measles – European Region |url=https://www.who.int/csr/don/06-may-2019-measles-euro/en/ |archive-url=https://web.archive.org/web/20190508120456/https://www.who.int/csr/don/06-may-2019-measles-euro/en/ |url-status=dead |archive-date=8 May 2019 |website=[[World Health Organization]] (WHO) |access-date=8 May 2019}}</ref>
[[File:En.Wikipedia-VideoWiki-Measles.webm|thumb|thumbtime=1:30|upright=1.4|Video summary ([[Wikipedia:VideoWiki/Measles|script]])]]
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==Signs and symptoms==
Symptoms typically begin 7–14 days (typically 11-12 days) after exposure with a [[prodrome]] of fever, [[malaise]], and [[cough]].<ref name="Pink Book" /><ref name="Merck Manual" /><ref name="Rot2016" /> The fever with measles increases in a stepwise fashion and peaks at {{Convert|103|F|C}} - {{Convert|105|F|C}}.<ref name="Pink Book" /> After one to two days of prodromal illness, [[Koplik's spots|Koplik spots]] appear inside the cheeks opposite the molars as clusters of white lesions ("grains of salt") on reddened areas. They are [[pathognomonic]] for measles, but are present for only a short time and therefore are not always seen.<ref name="Merck Manual" /> The classic symptoms include a fever, [[cough]], [[coryza]] (head cold, fever, sneezing), and [[conjunctivitis]], referred to as "the three C's", and a [[maculopapular rash]].<ref name=Biesbroeck2013>{{cite journal | vauthors = Biesbroeck L, Sidbury R | title = Viral exanthems: an update | journal = Dermatologic Therapy | volume = 26 | issue = 6 | pages = 433–8 | date = November 2013 | pmid = 24552405 | doi = 10.1111/dth.12107 | s2cid = 10496269 | doi-access = free | title-link = doi }}</ref>

The characteristic measles [[rash]] is classically described as a generalized red maculopapular rash that begins three to five days after the prodrome; on average, 14 days after exposure, but as few as 7 or as many as 21 days post-exposure.<ref name="Pink Book" /><ref name="Rot2016" /> The rash starts on the back of the ears or on the face and thereafter spreads to the rest of the body. It is caused by the cellular and humoral immune system's clearing of infected skin cells, as is the conjunctivitis. Measles conjunctivitis often also causes [[photophobia]].<ref name="Rot2016" /> The rash is said to "stain", changing color from red to dark brown, before disappearing.

Uncomplicated cases of measles typically improve within days of rash onset and resolve within 7–10 days.<ref name="Rot2016" />

People who have been vaccinated against measles but have incomplete protective immunity may experience a form of modified measles. Modified measles is characterized by a prolonged [[incubation period]], milder, and less characteristic symptoms (sparse and discrete rash of short duration).<ref name="Pink Book" /> Because development of the rash and conjunctivitis requires a functional immune system, immunocompromised people may not be diagnosed as readily.<ref name="Rot2016" /><gallery mode="packed" heights="150" style="text-align:left">
File:Measles child Philippines.jpg|A Filipino baby with measles
File:Koplik spots, measles 6111 lores.jpg|[[Koplik's spots]] on the third pre-eruptive day
File:Morbillivirus measles infection.jpg|Abdominal maculopapular rash on day 3 of illness
</gallery>

===Complications===
Complications of measles are relatively common. Some are caused directly by the virus, while others are caused by viral suppression of the immune system. This phenomenon, known as "immune amnesia", increases the risk of [[Superinfection|secondary bacterial infections]];<ref name="Rot2016" /><ref>{{cite journal |vauthors=Griffin DE |date=July 2010 |title=Measles virus-induced suppression of immune responses |journal=Immunological Reviews |volume=236 |pages=176–89 |doi=10.1111/j.1600-065X.2010.00925.x |pmc=2908915 |pmid=20636817}}</ref><ref name="Amnesia">{{cite web |last=Griffin |first=Ashley Hagen |date=18 May 2019 |title=Measles and Immune Amnesia |url=https://asm.org/Articles/2019/May/Measles-and-Immune-Amnesia |url-status=live |archive-url=https://archive.today/20200118042959/https://asm.org/Articles/2019/May/Measles-and-Immune-Amnesia |archive-date=18 January 2020 |access-date=18 January 2020 |website=asm.org |publisher=American Society for Microbiology}}</ref><ref name="Mina 2019" /> two months after recovery there is an 11–73% decrease in the number of antibodies against other bacteria and viruses.<ref name="Nature">{{cite journal|title=Measles erases immune 'memory' for other diseases|url=https://www.nature.com/articles/d41586-019-03324-7|journal=Nature|access-date=3 November 2019|date=31 October 2019|doi=10.1038/d41586-019-03324-7|last=Guglielmi|first=Giorgia|pmid=33122832|s2cid=208489179|archive-date=2 November 2019|archive-url=https://web.archive.org/web/20191102065033/https://www.nature.com/articles/d41586-019-03324-7|url-status=live|url-access=subscription}}</ref> Population studies from prior to the introduction of the measles vaccine suggest that immune amnesia typically lasts 2–3 years. Primate studies suggest that immune amnesia in measles is effected by replacement of [[Lymphocyte|memory lymphocytes]] with ones that are specific to measles virus, since they are destroyed after being infected by the virus. This creates lasting immunity to measles re-infection, but decreases immunity to other pathogens.<ref name="Amnesia" /> Complications may be directly related to the virus - e.g. [[viral pneumonia]] or viral [[laryngotracheobronchitis]] (croup) - or related to the damage measles virus causes to tissues and the immune system. The most serious direct complications include acute encephalitis,<ref>{{cite journal |vauthors=Fisher DL, Defres S, Solomon T |date=March 2015 |title=Measles-induced encephalitis |journal=QJM |volume=108 |issue=3 |pages=177–82 |doi=10.1093/qjmed/hcu113 |pmid=24865261 | doi-access = free | title-link = doi }}</ref> [[corneal ulcer]]ation (leading to [[corneal abrasion|corneal scarring]]);<ref>{{cite journal |vauthors=Semba RD, Bloem MW |date=March 2004 |title=Measles blindness |journal=Survey of Ophthalmology |volume=49 |issue=2 |pages=243–55 |doi=10.1016/j.survophthal.2003.12.005 |pmid=14998696}}</ref> and [[subacute sclerosing panencephalitis]], a progressive and fatal inflammation of the brain that occurs in about 1 in 600 unvaccinated infants under 15 months. Common secondary infections include [[infectious diarrhea]], [[bacterial pneumonia]], and [[otitis media]].<ref name="Rot2016" />

The death rate in the 1920s was around 30% for measles pneumonia.<ref>{{cite journal | vauthors = Ellison JB | title = Pneumonia in Measles | journal = Archives of Disease in Childhood | volume = 6 | issue = 31 | pages = 37–52 | date = February 1931 | pmid = 21031836 | pmc = 1975146 | doi = 10.1136/adc.6.31.37 }}</ref> People who are at high risk for complications are infants and children aged less than 5 years;<ref name=Medscape2018/> adults aged over 20 years;<ref name=Medscape2018/> pregnant women;<ref name=Medscape2018/> people with compromised immune systems, such as from [[leukemia]], HIV infection or innate immunodeficiency;<ref name=Medscape2018/><ref name="cdc.gov">{{cite web|title=Measles |url=https://www.cdc.gov/measles/hcp/clinical-overview/ |website=U.S. [[Centers for Disease Control and Prevention]] (CDC)|access-date=22 October 2016|url-status=live|archive-url=https://web.archive.org/web/20161023051702/https://www.cdc.gov/measles/hcp/index.html|archive-date=23 October 2016 }}</ref> and those who are [[malnutrition|malnourished]]<ref name=Medscape2018/> or have [[vitamin A deficiency]].<ref name=Medscape2018/><ref>{{cite web|url=https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/|title=Vitamin A|author=National Institutes of Health Office of Dietary Supplements|year=2013|publisher=U.S. Department of Health & Human Services|access-date=11 March 2015|url-status=live|archive-url=https://web.archive.org/web/20150311000932/http://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/|archive-date=11 March 2015}}</ref> Complications are usually more severe in adults.<ref>{{cite journal | vauthors = Sabella C | title = Measles: not just a childhood rash | journal = Cleveland Clinic Journal of Medicine | volume = 77 | issue = 3 | pages = 207–13 | date = March 2010 | pmid = 20200172 | doi = 10.3949/ccjm.77a.09123 | s2cid = 4743168 | doi-access = free | title-link = doi }}</ref> Between 1987 and 2000, the case fatality rate across the United States was three deaths per 1,000 cases attributable to measles, or 0.3%.<ref name="The Clinical Significance of Measles: A Review">{{cite journal | vauthors = Perry RT, Halsey NA | title = The clinical significance of measles: a review | journal = The Journal of Infectious Diseases | volume = 189 Suppl 1 | issue = S1 | pages = S4-16 | date = May 2004 | pmid = 15106083 | doi = 10.1086/377712 | doi-access = free | title-link = doi }}</ref> In [[developing country|underdeveloped nations]] with high rates of malnutrition and poor [[healthcare]], fatality rates have been as high as 28%.<ref name="The Clinical Significance of Measles: A Review"/> In immunocompromised persons (e.g., people with [[AIDS]]) the fatality rate is approximately 30%.<ref name="Sension1988">{{cite journal | vauthors = Sension MG, Quinn TC, Markowitz LE, Linnan MJ, Jones TS, Francis HL, Nzilambi N, Duma MN, Ryder RW | title = Measles in hospitalized African children with human immunodeficiency virus | journal = American Journal of Diseases of Children | volume = 142 | issue = 12 | pages = 1271–2 | date = December 1988 | pmid = 3195521 | doi = 10.1001/archpedi.1988.02150120025021 }}</ref>

Even in previously healthy children, measles can cause serious illness requiring hospitalization.<ref name="cdc.gov"/> One out of every 1,000 measles cases progresses to acute [[encephalitis]], which often results in permanent brain damage.<ref name="cdc.gov"/> One to three out of every 1,000 children who become infected with measles will die from respiratory and neurological complications.<ref name="cdc.gov"/>

==Cause==
[[File:Measles virus.JPG|thumb|upright=1.3|An electron micrograph of the measles virus]]
Measles is caused by the [[measles virus]], a single-stranded, non-segmented, [[Sense (molecular biology)#RNA sense in viruses|negative-sense]], [[Viral envelope|enveloped]] [[RNA virus]] of the genus ''[[Morbillivirus]]'' within the family ''[[Paramyxoviridae]]''.<ref name=":16" /><ref name="Bester2016" /> It is related most closely to [[rinderpest]], a cattle virus eradicated in 2001, and [[canine distemper]], a mammalian disease that causes neurologic deterioration.<ref name="Pink Book" /> There are 24 [[Strain (biology)|strains]] of measles virus divided into eight [[clade]]s designated A-H.<ref name=":16" />

The virus is one of the most contagious human pathogens and is spread by coughing and sneezing via close personal contact or direct contact with secretions.<ref name="cdc.gov" /><ref name="Bester2016" /><ref name=":16">{{Cite journal |last1=Hübschen |first1=Judith M. |last2=Gouandjika-Vasilache |first2=Ionela |last3=Dina |first3=Julia |date=12 February 2022 |title=Measles |url=https://pubmed.ncbi.nlm.nih.gov/35093206 |journal=Lancet |volume=399 |issue=10325 |pages=678–690 |doi=10.1016/S0140-6736(21)02004-3 |issn=1474-547X |pmid=35093206}}</ref> It remains infectious for up to two hours via suspended respiratory droplets.<ref name="Pink Book" /> It is not easily spread by [[fomite]]s, because the virus is inactivated within a few hours by [[Ultraviolet|ultraviolet light]] and heat.<ref name="Rot2016" /> It is also inactivated by [[trypsin]], acidic environments, and [[ether]].<ref name="Pink Book" /> Measles is so contagious that if one person has it, 90% of non-immune people who have close contact with them (e.g., household members) will also become infected.<ref name="Pink Book" /><ref name="pmid31480896">{{cite journal | vauthors=Banerjee E, Griffith J, Kenyon C, Christianson B, Strain A, Martin K | display-authors=etal | title=Containing a measles outbreak in Minnesota, 2017: methods and challenges. | journal=Perspect Public Health | year=2020 | volume=140 | issue=3 | pages=162–171 | pmid=31480896 | doi=10.1177/1757913919871072 | pmc= | s2cid=201829328 | url=https://pubmed.ncbi.nlm.nih.gov/31480896 | archive-date=2 May 2023 | archive-url=https://web.archive.org/web/20230502182530/https://journals.sagepub.com/doi/10.1177/1757913919871072?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed | url-status=live }}</ref> Humans are the only natural hosts of the virus, and no other animal [[Natural reservoir|reservoirs]] are known to exist, although mountain gorillas are believed to be susceptible to the disease.<ref name="Pink Book" /><ref name="pmid24450064">{{cite journal |vauthors=Spelman LH, Gilardi KV, Lukasik-Braum M, Kinani JF, Nyirakaragire E, Lowenstine LJ | display-authors=etal | title=Respiratory disease in mountain gorillas (Gorilla beringei beringei) in Rwanda, 1990-2010: outbreaks, clinical course, and medical management. | journal=J Zoo Wildl Med | year=2013 | volume=44 | issue=4 | pages=1027–35 | pmid=24450064 | doi=10.1638/2013-0014R.1 | pmc= | url=https://pubmed.ncbi.nlm.nih.gov/24450064| archive-date=2 May 2023 | archive-url=https://web.archive.org/web/20230502182527/https://bioone.org/journals/journal-of-zoo-and-wildlife-medicine/volume-44/issue-4/2013-0014R.1/RESPIRATORY-DISEASE-IN-MOUNTAIN-GORILLAS-GORILLA-BERINGEI-BERINGEI-IN-RWANDA/10.1638/2013-0014R.1.short | url-status=live }}</ref>
Risk factors for measles virus infection include [[immunodeficiency]] caused by [[HIV/AIDS]],<ref>{{cite journal | vauthors = Gowda VK, Sukanya V | title = Acquired immunodeficiency syndrome with subacute sclerosing panencephalitis | journal = Pediatric Neurology | volume = 47 | issue = 5 | pages = 379–81 | date = November 2012 | pmid = 23044024 | doi = 10.1016/j.pediatrneurol.2012.06.020 }}</ref> [[immunosuppression]] following receipt of an [[Organ transplantation|organ]] or a [[hematopoietic stem cell transplantation|stem cell transplant]],<ref>{{cite journal | vauthors = Waggoner JJ, Soda EA, Deresinski S | title = Rare and emerging viral infections in transplant recipients | journal = Clinical Infectious Diseases | volume = 57 | issue = 8 | pages = 1182–8 | date = October 2013 | pmid = 23839998 | doi = 10.1093/cid/cit456 | pmc = 7107977 | doi-access = free | title-link = doi }}</ref> [[Alkylation|alkylating agents]], or [[Corticosteroid#Medical uses|corticosteroid therapy]], regardless of immunization status;<ref name=Medscape2018/> travel to areas where measles commonly occurs or contact with travelers from such an area;<ref name=Medscape2018/> and the loss of passive, inherited antibodies before the age of routine immunization.<ref name=Leuridan2012/>

==Pathophysiology==
[[File:MeaslesOsmosisPic5.jpg|thumb|upright=1.4|Drawing of the measles virus attaching to the lining of the trachea]]
[[File:Morbillo.jpg|thumb|Photomicrograph of a [[lung]] tissue specimen, showing the [[histopathology|histopathologic]] changes encountered in a case of measles [[pneumonia]]. Included in this view are numerous [[leukocyte]]s and a [[multinucleated giant cell]]. Normal alveolar [[cytoarchitecture]] has been obliterated.<ref>{{cite web |title=This photomicrograph of a lung tissue specimen, reveals the histopathologic changes encountered in a case of measles pneumonia. Included in this view, are numerous leukocytes, and a multinucleated giant cell. Normal alveolar cytoarchitecture has been obliterated. |id=859 |url=https://phil.cdc.gov/details.aspx?pid=859 |website=CDC, Public Health Image Library |publisher=U.S. Government |access-date=16 January 2024 |date=1972 |first1=Edwin P. |last1=Ewing Jr. |url-status=live |archive-url=https://web.archive.org/web/20231210152253/https://phil.cdc.gov/details.aspx?pid=859 |archive-date= 10 December 2023 }}</ref>]]

Once the measles virus contacts the [[Mucous membrane|mucosa]] lining the respiratory tract, it binds to [[SLAMF1|SLAM]] (signaling lymphocyte activation molecule, also known as CD150) on the surface of [[macrophage]]s and [[dendritic cell]]s. These cells then take up the virus. This process is mediated by the [[hemagglutinin]] protein (H) on the surface of the measles virus binding to SLAM and causing the fusion protein in the viral capsule (F) to change shape, allowing the envelope to fuse with the viral RNA and viral proteins entry. The L protein, an [[RNA-dependent RNA polymerase]], then transcribes the viral [[Sense (molecular biology)|negative-sense genome]] into a positive-sense [[Messenger RNA|mRNA]], which is [[Translation (biology)|translated]] by the cell's native [[ribosome]]s into viral proteins. These immune cells pass the virus on to other groups of immune cells, including [[B cell]]s, [[T cells]], [[thymocyte]]s, and [[hematopoietic stem cell]]s, which disseminate the virus to other organs during the [[incubation period]].<ref name="Pink Book">{{cite book |date=24 April 2024 |chapter=Chapter 13: Measles |url=https://www.cdc.gov/pinkbook/hcp/table-of-contents/chapter-13-measles.html |url-status=live |archive-url=https://web.archive.org/web/20240719164140/https://www.cdc.gov/pinkbook/hcp/table-of-contents/chapter-13-measles.html |archive-date=19 July 2024 |access-date=9 April 2025 |title=Pink Book Epidemiology and Prevention of Vaccine-Preventable Diseases |publisher=U.S. [[Centers for Disease Control and Prevention]] (CDC)}}</ref><ref name=":16" />

The initial period of infection in the lung lasts for two to three days, and ends with the first period of viremia. Five to seven days after infection begins, the second viremia occurs, and the virus infects epithelial cells.<ref name="Pink Book" /> The virus spreads along epithelial cells, initially in the respiratory tree via intercellular pores, and later in the linings of other organs and the respiratory tree via [[nectin-4]] receptors. This causes the cough seen clinically, which aerosolizes the virus and enables it to spread.<ref name="Pink Book" /><ref name="Rot2016" />

==Diagnosis==
Typically, clinical [[diagnosis]] begins with the onset of [[fever]] and [[malaise]] about 10 days after exposure to the measles virus, followed by the emergence of [[cough]], [[coryza]], and [[conjunctivitis]] that worsen in severity over 4 days of appearing.<ref>{{Citation|last1=Rainwater-Lovett|first1=Kaitlin|title=Measles (Rubeola)|date=2018|url=https://accessmedicine.mhmedical.com/content.aspx?bookid=2129&sectionid=192025856|work=Harrison's Principles of Internal Medicine|editor-last=Jameson|editor-first=J. Larry|edition=20|place=New York, NY|publisher=McGraw-Hill Education|access-date=7 December 2020|last2=Moss|first2=William J.|editor2-last=Fauci|editor2-first=Anthony S.|editor3-last=Kasper|editor3-first=Dennis L.|editor4-last=Hauser|editor4-first=Stephen L.|archive-date=24 September 2020|archive-url=https://web.archive.org/web/20200924221558/http://accessmedicine.mhmedical.com/content.aspx?bookid=2129&sectionid=192025856|url-status=live}}</ref> Observation of Koplik's spots is also diagnostic.<ref name="baxby">{{cite journal |author-link=Derrick Baxby |vauthors=Baxby D |date=July 1997 |title=The diagnosis of the invasion of measles from a study of the exanthema as it appears on the buccal mucous membraneBy Henry Koplik, M.D. Reproduced from Arch. Paed. 13, 918-922 (1886) |journal=Reviews in Medical Virology |volume=7 |issue=2 |pages=71–74 |doi=10.1002/(SICI)1099-1654(199707)7:2<71::AID-RMV185>3.0.CO;2-S |pmid=10398471 |s2cid=42670134}}</ref> Other diseases that may appear similar to measles include [[dengue fever]], [[rubella]], [[Fifth disease|erythema infectiosum]] (also called fifth disease, caused by [[parvovirus B19]]), and [[roseola]] (also called exanthem subitum or sixth disease, caused by [[Human herpesvirus 6|HHV6]]).<ref name="Rot2016" /> Laboratory confirmation is therefore strongly recommended, especially in non-endemic areas.<ref name="Pink Book" />

===Laboratory testing===
Laboratory diagnosis of measles can be done with confirmation of positive measles [[IgM antibodies]] or detection of measles virus RNA from throat, nasal or urine specimen by using the [[reverse transcription polymerase chain reaction]] assay.<ref name=":6">{{cite web|url=https://www.cdc.gov/vaccines/pubs/surv-manual/chpt07-measles.html|title=Surveillance Manual {{!}} Measles {{!}} Vaccine Preventable Diseases |date=23 May 2019|website=U.S. [[Centers for Disease Control and Prevention]] (CDC)|access-date=25 November 2019|archive-date=4 August 2020|archive-url=https://web.archive.org/web/20200804015227/https://www.cdc.gov/vaccines/pubs/surv-manual/chpt07-measles.html|url-status=live}}</ref><ref name=":5"/> This method is particularly useful to confirm cases when the IgM antibodies results are inconclusive.<ref name=":6"/> For people unable to have their [[phlebotomy|blood drawn]], saliva can be collected for salivary measles-specific [[IgA]] testing.<ref name=":5">{{cite journal | vauthors = Friedman M, Hadari I, Goldstein V, Sarov I | title = Virus-specific secretory IgA antibodies as a means of rapid diagnosis of measles and mumps infection | journal = Israel Journal of Medical Sciences | volume = 19 | issue = 10 | pages = 881–4 | date = October 1983 | pmid = 6662670 }}</ref> Salivary tests used to diagnose measles involve collecting a saliva sample and testing for the presence of measles antibodies.<ref name=":3">{{Cite journal|last1=Dimech|first1=Wayne|last2=Mulders|first2=Mick N.|date=July 2016|title=A review of testing used in seroprevalence studies on measles and rubella|journal=Vaccine|volume=34|issue=35|pages=4119–4122|doi=10.1016/j.vaccine.2016.06.006|pmid=27340096}}</ref><ref name=":4">{{cite journal |last1=Simon |first1=Jakub K. |last2=Ramirez |first2=Karina |last3=Cuberos |first3=Lilian |last4=Campbell |first4=James D. |last5=Viret |first5=Jean F. |last6=Muñoz |first6=Alma |last7=Lagos |first7=Rosanna |last8=Levine |first8=Myron M. |last9=Pasetti |first9=Marcela F. |title=Mucosal IgA Responses in Healthy Adult Volunteers following Intranasal Spray Delivery of a Live Attenuated Measles Vaccine |journal=Clinical and Vaccine Immunology |date=March 2011 |volume=18 |issue=3 |pages=355–361 |doi=10.1128/CVI.00354-10 |pmid=21228137 |pmc=3067370 }}</ref> This method is not ideal, as saliva contains many other fluids and proteins which may make it difficult to collect samples and detect measles antibodies.<ref name=":3"/><ref name=":4"/> Saliva also contains 800 times fewer antibodies than blood samples do, which makes salivary testing additionally difficult. Positive contact with other people known to have measles adds evidence to the diagnosis.<ref name=":3"/>

Biopsies and [[Histopathology|histopathologic]] examinations are not typically used to diagnose measles, but [[Warthin–Finkeldey cell]]s, giant cells with multiple nuclei and eosinophilic inclusions, are frequently seen in affected [[Lymphatic system|lymphoid]] tissue but are not unique to measles.<ref name="Mil2015" /><ref name=":15">{{Cite web |last=Weisenberg |first=Elliot |date=9 August 2022 |title=Measles |url=https://www.pathologyoutlines.com/topic/lungnontumormeasles.html |access-date=9 April 2025 |website=PathologyOutlines.com |archive-date=30 June 2024 |archive-url=https://web.archive.org/web/20240630182204/https://www.pathologyoutlines.com/topic/lungnontumormeasles.html |url-status=live }}</ref> Affected [[epithelium]] may have giant cells with [[viral inclusion bodies]] or [[Cowdry bodies]].<ref name=":15" />

==Prevention==
{{further|Measles vaccine|MMR vaccine|MMRV vaccine}}
[[File:Measles vaccination coverage world.svg|thumb|upright=1.4|Rates of measles vaccination worldwide]]
Mothers who are immune to measles pass antibodies to their children while they are still in the womb, especially if the mother acquired immunity through infection rather than vaccination.<ref name="Pink Book" /><ref name="Leuridan2012">{{cite journal | vauthors = Leuridan E, Sabbe M, Van Damme P | title = Measles outbreak in Europe: susceptibility of infants too young to be immunized | journal = Vaccine | volume = 30 | issue = 41 | pages = 5905–13 | date = September 2012 | pmid = 22841972 | doi = 10.1016/j.vaccine.2012.07.035 }}</ref> Such antibodies will usually give newborn infants some immunity against measles, but these antibodies are gradually lost over the course of the first nine months of life.<ref name="Merck Manual" /><ref name="Leuridan2012"/> However, immunization with live vaccines is not recommended in pregnancy; pregnant people found to be non-immune to measles should be immunized after delivery.<ref name=":13" /> Infants under one year of age whose maternal anti-measles antibodies have disappeared become susceptible to infection with the measles virus.<ref name="Leuridan2012"/>

It is generally recommended that children be immunized against measles at 12 months, as part of a three-part [[MMR vaccine]] (measles, [[mumps]], and [[rubella]]). The vaccine is generally not given before this age because younger infants respond inadequately to the vaccine due to an immature immune system. A second dose of the vaccine is recommended between the ages of four and five, to increase rates of immunity.<ref name="ACIP2013" /><ref name=":14">{{Cite web |date=28 April 2017 |title=Measles vaccines: WHO position paper |url=https://www.who.int/teams/immunization-vaccines-and-biologicals/policies/position-papers/measles |access-date=23 March 2025 |website=[[World Health Organization]] (WHO) |archive-date=14 February 2025 |archive-url=https://web.archive.org/web/20250214032347/https://www.who.int/teams/immunization-vaccines-and-biologicals/policies/position-papers/measles |url-status=live }}</ref> Adverse reactions to vaccination are rare, with fever and pain at the injection site being the most common. Life-threatening adverse reactions occur in less than one per million vaccinations (<0.0001%).<ref name="cubavac">{{cite journal | vauthors = Galindo BM, Concepción D, Galindo MA, Pérez A, Saiz J | title = Vaccine-related adverse events in Cuban children, 1999-2008 | journal = MEDICC Review | volume = 14 | issue = 1 | pages = 38–43 | date = January 2012 | pmid = 22334111 | doi = 10.37757/MR2012V14.N1.8 | doi-access = free | title-link = doi }}</ref>

In areas with a high risk of measles infection, the [[World Health Organization]] (WHO) recommends the first two doses of vaccine be given earlier, at nine and eighteen months of age.<ref name=":14" /> The vaccine should be given whether the child is HIV-infected or not.<ref>{{cite journal | vauthors = Helfand RF, Witte D, Fowlkes A, Garcia P, Yang C, Fudzulani R, Walls L, Bae S, Strebel P, Broadhead R, Bellini WJ, Cutts F | title = Evaluation of the immune response to a 2-dose measles vaccination schedule administered at 6 and 9 months of age to HIV-infected and HIV-uninfected children in Malawi | journal = The Journal of Infectious Diseases | volume = 198 | issue = 10 | pages = 1457–65 | date = November 2008 | pmid = 18828743 | doi = 10.1086/592756 | doi-access = free | title-link = doi }}</ref> The vaccine is less effective in HIV-infected infants than in the general population, but early treatment with antiretroviral drugs can increase its effectiveness.<ref>{{cite journal | vauthors = Ołdakowska A, Marczyńska M | title = [Measles vaccination in HIV infected children] | journal = Medycyna Wieku Rozwojowego | volume = 12 | issue = 2 Pt 2 | pages = 675–80 | year = 2008 | pmid = 19418943 }}</ref> Measles vaccination programs are often used to deliver other child health interventions as well, such as bed nets to protect against [[malaria]], antiparasitic medicine, and vitamin A supplements, and so contribute to the reduction of child deaths from other causes.<ref>{{cite press release|url=http://www.unicef.org/media/media_38076.html|title=Global goal to reduce measles deaths in children surpassed|publisher=UNICEF|year=2007|access-date=11 March 2015|url-status=dead|archive-url=https://web.archive.org/web/20150204152400/http://www.unicef.org/media/media_38076.html|archive-date=4 February 2015 }}</ref>

The [[Advisory Committee on Immunization Practices]] (ACIP) of the US [[Centers for Disease Control and Prevention]] (CDC) recommends that all adult international travelers who do not have positive evidence of previous measles immunity receive two doses of MMR vaccine before traveling.<ref name="ACIP2013" /><ref>{{cite web | title=Plan for Travel | website=Measles (Rubeola) | date=15 July 2024 | url=https://www.cdc.gov/measles/travel/index.html | access-date=3 May 2025 | archive-date=28 April 2025 | archive-url=https://web.archive.org/web/20250428062450/https://www.cdc.gov/measles/travel/index.html | url-status=live }}</ref> Birth before 1957 is presumptive evidence of immunity.<ref name="ACIP2013" /> People born before 1957 are likely to have been naturally infected with the measles virus and generally need not be considered susceptible.<ref name="ACIP2013">{{cite journal | vauthors = McLean HQ, Fiebelkorn AP, Temte JL, Wallace GS | title = Prevention of measles, rubella, congenital rubella syndrome, and mumps, 2013: summary recommendations of the Advisory Committee on Immunization Practices (ACIP) | journal = MMWR. Recommendations and Reports | volume = 62 | issue = RR-04 | pages = 2, 19 | date = June 2013 | pmid = 23760231 | url = https://www.cdc.gov/mmwr/pdf/rr/rr6204.pdf|url-status=live|archive-url=https://web.archive.org/web/20200413110343/https://www.cdc.gov/mmwr/pdf/rr/rr6204.pdf |archive-date= 13 April 2020}}</ref><ref name="Pink Book" /><ref>{{cite web |title=Measles Prevention: Recommendations of the Immunization Practices Advisory Committee (ACIP) |website=U.S. [[Centers for Disease Control and Prevention]] (CDC) |date=29 December 1989 |access-date=13 November 2020 |url=https://www.cdc.gov/mmwr/preview/mmwrhtml/00041753.htm |archive-date=15 May 2012 |archive-url=https://web.archive.org/web/20120515055632/http://www.cdc.gov/mmwr/preview/mmwrhtml/00041753.htm |url-status=live }}</ref>

There have been false claims of an association between the measles vaccine and [[autism]]; this incorrect concern has reduced the rate of vaccination and increased the number of cases of measles where immunization rates became too low to maintain [[herd immunity]].<ref name=Medscape2018/> Additionally, there have been false claims that measles infection protects against cancer.<ref name="Russell2019"/>

Administration of the MMR vaccine may prevent measles after exposure to the virus (post-exposure prophylaxis).<ref name=":10">{{cite journal |last1=Di Pietrantonj |first1=Carlo |last2=Rivetti |first2=Alessandro |last3=Marchione |first3=Pasquale |last4=Debalini |first4=Maria Grazia |last5=Demicheli |first5=Vittorio |title=Vaccines for measles, mumps, rubella, and varicella in children |journal=The Cochrane Database of Systematic Reviews |date=22 November 2021 |volume=2021 |issue=11 |pages=CD004407 |doi=10.1002/14651858.CD004407.pub5 |pmid=34806766 |pmc=8607336 |issn=1469-493X}}</ref> Post-exposure prophylaxis guidelines are specific to jurisdiction and population.<ref name=":10"/> [[Immunization|Passive immunization]] against measles by an [[intramuscular injection]] of antibodies could be effective up to the seventh day after exposure.<ref name="pmid24687262">{{Cite journal|last1=Young|first1=MK|last2=Nimmo|first2=GR|last3=Cripps|first3=AW|last4=Jones|first4=MA|date=April 2014|title=Post-exposure passive immunisation for preventing measles|url=https://doi.org/10.1002/14651858.CD010056.pub2|journal=Cochrane Database of Systematic Reviews |volume=2014 |issue=4 |pages=CD010056 |doi=10.1002/14651858.cd010056.pub2|pmid=24687262|pmc=11055624 |issn=1465-1858|hdl=10072/65474|hdl-access=free}}</ref> Compared to no treatment, the risk of measles infection is reduced by 83%, and the risk of death by measles is reduced by 76%. However, the effectiveness of passive immunization in comparison to active measles vaccine is not clear.<ref name="pmid24687262"/>

The MMR vaccine is 95% effective for preventing measles after one dose if the vaccine is given to a child who is twelve months of age or older; if a second dose of the MMR vaccine is given, it will provide immunity in 97-99% of children.<ref name="cdc.gov" /><ref name="Bester2016">{{Cite journal|last=Bester|first=JC|date=December 2016|title=Measles and Measles Vaccination: A Review |journal=JAMA Pediatrics |volume=170|issue=12|pages=1209–15 |doi=10.1001/jamapediatrics.2016.1787|pmid=27695849|issn=2168-6203}}</ref>

===Vitamin A and measles prevention===
"Vitamin A deficiency (VAD) is a major public health problem in low- and middle-income countries, affecting 190 million children under five years of age and leading to many adverse health consequences, including death."<ref name="Cochrane2022"/> Vitamin A deficiency is rare in the United States.<ref name=":8">{{Cite web |title=Office of Dietary Supplements - Vitamin A and Carotenoids |url=https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/ |access-date=8 April 2025 |website=ods.od.nih.gov |archive-date=12 December 2016 |archive-url=https://web.archive.org/web/20161212224704/https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/ |url-status=live }}</ref> A meta-analysis of clinical trials conducted in countries where VAD is prevalent concluded that when children were supplemented with vitamin A, there was a 50% reduction in incidence of contracting measles.<ref name="Cochrane2022">{{cite journal |vauthors=Imdad A, Mayo-Wilson E, Haykal MR, Regan A, Sidhu J, Smith A, Bhutta ZA |title=Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age |journal=Cochrane Database Syst Rev |volume=3 |issue=3 |pages=CD008524 |date=March 2022 |pmid=35294044 |pmc=8925277 |doi=10.1002/14651858.CD008524.pub4 }}</ref> By way of comparison, vaccination with two doses of the measles vaccine in childhood provides 97-99% protection at preventing measles.<ref name="cdc.gov" /><ref name="ACIP2013" /><ref name="Bester2016" /> Vitamin A supplementation is not thought to reduce the risk of death from measles.<ref name=":8" /> Children given high doses of vitamin A from supplements or [[cod liver oil]] can accumulate to toxic levels and this can lead to [[hypervitaminosis A]] and [[Liver disease|liver damage]].<ref name=":8" />

A 2016 [[Cochrane review]] of two randomised controlled trials (RCTs) involving 260 children with measles compared vitamin A to placebo. Crucially, neither study reported blindness or other ocular morbidities as primary outcomes. One trial showed a temporary increase in serum retinol levels, but no sustained effect or impact on weight gain. The second trial found no significant difference in serum retinol levels or rates of undernutrition. Therefore, the authors concluded that no trials were found that assessed whether vitamin A supplementation in children with measles prevents [[Visual impairment|blindness]].<ref name="Cochrane2016">{{cite journal |vauthors=Bello S, Meremikwu MM, Ejemot-Nwadiaro RI, Oduwole O |title= Routine vitamin A supplementation for the prevention of blindness due to measles infection in children |journal=Cochrane Database Systematic Review |date=August 2016 |pmid= 27580345 |doi= 10.1002/14651858.CD007719.pub4}}</ref>

In the [[2025 Southwest United States measles outbreak]], centered in [[West Texas]], some families continued to refuse vaccines and instead opted for giving vitamin A supplements or vitamins A- and D-containing cod liver oil to their children after [[Robert F. Kennedy Jr.]], promoted vitamin A as prevention and treatment.<ref name="NYTimes">{{cite web | last=Rosenbluth | first=Teddy | title=For Some Measles Patients, Vitamin A Remedy Supported by RFK Jr. Leaves Them More Ill | website=The New York Times | date=25 March 2025 | url=https://www.nytimes.com/2025/03/25/health/measles-kennedy-vitamin-a.html | access-date=26 March 2025 | archive-date=25 March 2025 | archive-url=https://web.archive.org/web/20250325225627/https://www.nytimes.com/2025/03/25/health/measles-kennedy-vitamin-a.html | url-status=live }}</ref> Multiple children hospitalized for measles at Covenant Children's Hospital in Lubbock also showed signs of [[liver damage]], a symptom of vitamin A toxicity.<ref name=":8" /><ref name="NYTimes" /><ref name="Davies2025">{{cite web | last=Davies | first=David Martin | title=West Texas children treated for vitamin A toxicity as medical disinformation spreads alongside measles outbreak | website=TPR | date=28 March 2025 | url=https://www.tpr.org/public-health/2025-03-27/west-texas-children-treated-for-vitamin-a-toxicity-as-medical-disinformation-spreads-alongside-measles-outbreak | access-date=28 March 2025 | archive-date=19 April 2025 | archive-url=https://web.archive.org/web/20250419192912/https://www.tpr.org/public-health/2025-03-27/west-texas-children-treated-for-vitamin-a-toxicity-as-medical-disinformation-spreads-alongside-measles-outbreak | url-status=live }}</ref> As of May 2025, regardless of such serious side effects—and possibly resulting in increased disease spread—Kennedy, in his role as [[United States Secretary of Health and Human Services|Secretary of Health and Human Services]], has nevertheless continued to endorse vitamin A during the measles epidemic, along with other unscientific, non-vaccine measures, a response for which he has been widely criticized.<ref>{{Cite web |last=Fischman |first=Josh |date=May 5, 2025 |title=Do 'alternative' measles treatments touted by RFK Jr. work? |url=https://www.scientificamerican.com/article/do-alternative-measles-treatments-touted-by-rfk-jr-work/ |access-date=2025-05-09 |website=Scientific American |language=en}}</ref>

==Treatment==
There is no specific [[antiviral treatment]] if measles develops.<ref name="cdc.gov"/> Instead the medications are generally aimed at treating superinfections, maintaining good hydration with adequate fluids, and pain relief.<ref name="cdc.gov" /> [[Supportive treatment]] can include [[ibuprofen]] or [[paracetamol|paracetamol (acetaminophen)]] to reduce fever and pain and, if required, a fast-acting [[bronchodilator|medication to dilate the airways]] for cough.<ref>{{cite news |last=Rezaie |first=Salim R. |title=Measles: The Sequel |url=https://epmonthly.com/article/measles-the-sequel/ |access-date=7 June 2019 |work=Emergency Physicians Monthly |archive-date=7 June 2019 |archive-url=https://web.archive.org/web/20190607174307/https://epmonthly.com/article/measles-the-sequel/ |url-status=live }}</ref>

Some groups, such as young children and the severely malnourished, are also physician-administered [[vitamin A]], which acts as an [[Immunotherapy#Immunomodulators|immunomodulator]] that boosts the antibody responses to measles and decreases the risk of serious complications.<ref name="cdc.gov" /><ref name="Bester2016" /><ref name=Vac2017>{{cite journal | vauthors = ((World Health Organization)) | title = Measles vaccines: WHO position paper – April 2017 | journal = Weekly Epidemiological Record | volume = 92 | issue = 17 | pages = 205–27 | date = April 2017 | pmid = 28459148 | hdl=10665/255377 | hdl-access=free }}</ref><!-- Quote = Even in countries where measles is not usually severe, vitamin A should be given in all cases of severe measles --> While vitamin A treatment does not cure the disease or reduce mortality in every age group,<ref>{{cite web | url = https://www.doh.wa.gov/YouandYourFamily/IllnessandDisease/Measles/FrequentlyAskedQuestions | title = Frequently Asked Questions about Measles | publisher = Washington State Department of Health | quote = [Vitamin A] cannot prevent or cure the measles | access-date = 10 February 2019 | archive-date = 5 August 2019 | archive-url = https://web.archive.org/web/20190805214034/https://www.doh.wa.gov/YouandYourFamily/IllnessandDisease/Measles/FrequentlyAskedQuestions | url-status = live }}</ref> two doses (200,000 [[International unit|IU]]) of vitamin A was shown to reduce mortality in children younger than two years of age.<ref name="Bester2016" /><ref name="pmid16235283">{{cite journal | vauthors = Huiming Y, Chaomin W, Meng M | title = Vitamin A for treating measles in children | journal = The Cochrane Database of Systematic Reviews | issue = 4 | pages = CD001479 | date = October 2005 | volume = 2005 | pmid = 16235283 | doi = 10.1002/14651858.CD001479.pub3 | editor1-last = Yang | editor1-first = Huiming | pmc = 7076287 }}</ref> In the 2025 U.S. outbreak, children are presenting at hospitals with measles and hypervitaminosis A because their parents were administering vitamin A sources (supplements or [[cod liver oil]]) as attempts of protection before the children became ill with measles.<ref name="NYTimes" /><ref name="Davies2025" />

[[Zinc in biology|Zinc]] supplementation for children with measles has not been sufficiently studied.<ref>{{cite journal | vauthors = Awotiwon AA, Oduwole O, Sinha A, Okwundu CI | title = Zinc supplementation for the treatment of measles in children | journal = The Cochrane Database of Systematic Reviews | volume = 2017 | pages = CD011177 | date = June 2017 | issue = 6 | pmid = 28631310 | pmc = 6481361 | doi = 10.1002/14651858.CD011177.pub3 }}</ref> Similarly, there is no randomized clinical trial evidence for or against whether Chinese medicinal herbs are an effective treatment.<ref>{{Cite journal|last1=Chen|first1=Shou|last2=Wu|first2=Taixiang|last3=Kong|first3=Xiangyu|last4=Yuan|first4=Hao|date=9 November 2011|title=Chinese medicinal herbs for measles|journal=The Cochrane Database of Systematic Reviews|volume=2011 |issue=11|pages=CD005531|doi=10.1002/14651858.CD005531.pub4|issn=1469-493X|pmc=7265114|pmid=22071825}}</ref>

==Prognosis==
Most people survive measles, though in some cases, complications may occur. About 1 in 4 individuals will be hospitalized and 1–2 in 1,000 will die. Complications are more likely in children under age 5, adults over age 20, and pregnant people.<ref name=":13">{{Cite web |title=Management of Obstetric–Gynecologic Patients During a Measles Outbreak |url=https://www.acog.org/clinical/clinical-guidance/practice-advisory/articles/2024/03/management-of-obstetric-gynecologic-patients-during-a-measles-outbreak |access-date=21 March 2025 |website=www.acog.org }}</ref><ref>{{cite web |title=Measles Complications |url=https://www.cdc.gov/measles/symptoms/complications.html |website=U.S. [[Centers for Disease Control and Prevention]] (CDC) |access-date=14 May 2019 |date=25 February 2019 |archive-date=19 November 2019 |archive-url=https://web.archive.org/web/20191119142611/https://www.cdc.gov/measles/symptoms/complications.html |url-status=live }}</ref> [[Pneumonia]] is the most common fatal complication of measles infection and accounts for 56–86% of measles-related deaths.<ref>{{Cite journal |last1=Di Pietrantonj |first1=Carlo |last2=Rivetti |first2=Alessandro |last3=Marchione |first3=Pasquale |last4=Debalini |first4=Maria Grazia |last5=Demicheli |first5=Vittorio |date=22 November 2021 |title=Vaccines for measles, mumps, rubella, and varicella in children |journal=The Cochrane Database of Systematic Reviews |volume=2021 |issue=11 |pages=CD004407 |doi=10.1002/14651858.CD004407.pub5 |issn=1469-493X |pmc=8607336 |pmid=34806766}}</ref>

Possible consequences of measles virus infection include [[laryngotracheobronchitis]], [[sensorineural hearing loss]],<ref name=Cohen2014>{{cite journal | vauthors = Cohen BE, Durstenfeld A, Roehm PC | title = Viral causes of hearing loss: a review for hearing health professionals | journal = Trends in Hearing | volume = 18 | pages = 2331216514541361 | date = July 2014 | pmid = 25080364 | pmc = 4222184 | doi = 10.1177/2331216514541361 }}</ref> and—in about 1 in 10,000 to 1 in 300,000 cases<ref name=Noyce2012>{{cite journal | vauthors = Noyce RS, Richardson CD | title = Nectin 4 is the epithelial cell receptor for measles virus | journal = Trends in Microbiology | volume = 20 | issue = 9 | pages = 429–39 | date = September 2012 | pmid = 22721863 | doi = 10.1016/j.tim.2012.05.006 }}</ref>—[[Subacute sclerosing panencephalitis|panencephalitis]], which is usually fatal.<ref name="ninds.nih.gov">{{NINDS|subacute-sclerosing-panencephalitis|Subacute Sclerosing Panencephalitis}}</ref> Acute measles encephalitis is another serious risk of measles virus infection. It typically occurs two days to one week after the measles [[exanthem|rash]] breaks out and begins with very high fever, severe headache, [[convulsion]]s and altered mentation. A person with measles encephalitis may become [[coma]]tose, and death or brain injury may occur.<ref name="Merck Manual" />

For people having had measles, it is rare to ever have a symptomatic reinfection.<ref>{{cite journal | title = Recommendation of the Immunization Practices Advisory Committee (ACIP). Measles prevention | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 31 | issue = 17 | pages = 217–24, 229–31 | date = May 1982 | pmid = 6804783 | url = https://www.cdc.gov/mmwr/preview/mmwrhtml/00001090.htm | author1 = Centers for Disease Control (CDC) | access-date = 10 May 2019 | archive-date = 23 February 2021 | archive-url = https://web.archive.org/web/20210223235542/http://www.cdc.gov/mmwr/preview/mmwrhtml/00001090.htm | url-status = live }}</ref>

The measles virus can deplete previously acquired [[Immunological memory|immune memory]] by killing cells that make antibodies, and thus weakens the immune system, which can cause deaths from other diseases.<ref name = Amnesia/><ref name="Mina 2019">{{cite journal | vauthors = Mina MJ, Kula T, Leng Y, Li M, de Vries RD, Knip M, Siljander H, Rewers M, Choy DF, Wilson MS, Larman HB, Nelson AN, Griffin DE, de Swart RL, Elledge SJ | title = Measles virus infection diminishes preexisting antibodies that offer protection from other pathogens | journal = Science | volume = 366 | issue = 6465 | pages = 599–606 | date = 1 November 2019 | pmid = 31672891 | doi = 10.1126/science.aay6485 | pmc = 8590458 | issn = 0036-8075 | bibcode = 2019Sci...366..599M | hdl = 10138/307628 | doi-access = free | title-link = doi}}</ref><ref name = Nature/> Suppression of the immune system by measles lasts about two years and has been epidemiologically implicated in up to 90% of childhood deaths in [[Third World|third world]] countries, and historically may have caused rather more deaths in the United States, the UK and Denmark than were directly caused by measles.<ref name="pmid25954009" >{{cite journal |title=Long-term measles-induced immunomodulation increases overall childhood infectious disease mortality |journal=Science |date=May 2015 |doi=10.1126/science.aaa3662 |pmid=25954009 |pmc=4823017 |bibcode=2015Sci...348..694M |vauthors=Mina MJ, Metcalf CJ, de Swart RL, Osterhaus AD, Grenfell BT |volume=348 |issue=6235 |pages=694–9 | doi-access = free | title-link = doi }}</ref><ref>{{cite web | last=Bakalar | first=Nicholas | title=Measles May Increase Susceptibility to Other Infections | website=[[The New York Times]] | date=7 May 2015 | url=https://archive.nytimes.com/well.blogs.nytimes.com/2015/05/07/measles-may-increase-susceptibility-to-other-infections/ |access-date=7 June 2015 |archive-date=10 May 2015 |archive-url=https://web.archive.org/web/20150510032648/http://well.blogs.nytimes.com/2015/05/07/measles-may-increase-susceptibility-to-other-infections/ |url-status=live }}</ref> Although the measles vaccine contains an attenuated strain, it does not deplete immune memory.<ref name="Mina 2019"/>

==Epidemiology==
{{Main|Epidemiology of measles}}

[[File:Measles world map-Deaths per million persons-WHO2012.svg|thumb|upright=1.4|Deaths from measles per million persons in 2012 {{Div col|small=yes|colwidth=10em}}{{legend|#b3b3b3|no data}}{{legend|#ffff20|0}}{{legend|#ff9a20|1–8}}{{legend|#f08015|9–26}}{{legend|#e06815|27–38}}{{legend|#d85010|39–73}}{{legend|#d02010|74–850}}{{div col end}}]]
[[File:Measles world map - DALY - WHO2004.svg|thumb|upright=1.4|[[Disability-adjusted life year]] for measles per 100,000 inhabitants in 2004{{Div col|small=yes|colwidth=10em}}
{{legend|#b3b3b3|no data}}
{{legend|#ffff65|≤ 10}}
{{legend|#fff200|10–25}}
{{legend|#ffdc00|25–50}}
{{legend|#ffc600|50–75}}
{{legend|#ffb000|75–100}}
{{legend|#ff9a00|100–250}}
{{legend|#ff8400|250–500}}
{{legend|#ff6e00|500–750}}
{{legend|#ff5800|750–1000}}
{{legend|#ff4200|1000–1500}}
{{legend|#ff2c00|1500–2000}}
{{legend|#cb0000|≥ 2000}}
{{div col end}}]]

Measles is extremely infectious and its continued circulation in a community depends on the generation of susceptible hosts by birth of children. In communities that generate insufficient new hosts the disease will die out. This concept was first recognized in measles by M.S. Bartlett in 1957, who referred to the minimum number supporting measles as the [[critical community size]] (CCS).<ref>{{cite journal|last=Bartlett|first=M.S.|title=Measles periodicity and community size|journal=J. R. Stat. Soc.|year=1957|series=Ser. A|issue=120|pages=48–70}}</ref> Analysis of outbreaks in island communities suggested that the CCS for measles is around 250,000.<ref name=Black1966>{{cite journal | vauthors = Black FL | title = Measles endemicity in insular populations: critical community size and its evolutionary implication | journal = Journal of Theoretical Biology | volume = 11 | issue = 2 | pages = 207–11 | date = July 1966 | pmid = 5965486 | doi = 10.1016/0022-5193(66)90161-5 | bibcode = 1966JThBi..11..207B }}</ref> Due to the ease with which measles is transmitted from person to person in a community, more than 95% of the community must be vaccinated in order to achieve [[herd immunity]].<ref name=Ludlow2015/>

In 2011, the WHO estimated that 158,000 deaths were caused by measles. This is down from 630,000 deaths in 1990.<ref name=Loz2012>{{cite journal | vauthors = Lozano R, Naghavi M, Foreman K, Lim S, Shibuya K, Aboyans V, Abraham J, Adair T, Aggarwal R, Ahn SY, Alvarado M, Anderson HR, Anderson LM, Andrews KG, Atkinson C, Baddour LM, Barker-Collo S, Bartels DH, Bell ML, Benjamin EJ, Bennett D, Bhalla K, Bikbov B, Bin Abdulhak A, Birbeck G, Blyth F, Bolliger I, Boufous S, Bucello C, Burch M, Burney P, Carapetis J, Chen H, Chou D, Chugh SS, Coffeng LE, Colan SD, Colquhoun S, Colson KE, Condon J, Connor MD, Cooper LT, Corriere M, Cortinovis M, de Vaccaro KC, Couser W, Cowie BC, Criqui MH, Cross M, Dabhadkar KC, Dahodwala N, De Leo D, Degenhardt L, Delossantos A, Denenberg J, Des Jarlais DC, Dharmaratne SD, Dorsey ER, Driscoll T, Duber H, Ebel B, Erwin PJ, Espindola P, Ezzati M, Feigin V, Flaxman AD, Forouzanfar MH, Fowkes FG, Franklin R, Fransen M, Freeman MK, Gabriel SE, Gakidou E, Gaspari F, Gillum RF, Gonzalez-Medina D, Halasa YA, Haring D, Harrison JE, Havmoeller R, Hay RJ, Hoen B, Hotez PJ, Hoy D, Jacobsen KH, James SL, Jasrasaria R, Jayaraman S, Johns N, Karthikeyan G, Kassebaum N, Keren A, Khoo JP, Knowlton LM, Kobusingye O, Koranteng A, Krishnamurthi R, Lipnick M, Lipshultz SE, Ohno SL, Mabweijano J, MacIntyre MF, Mallinger L, March L, Marks GB, Marks R, Matsumori A, Matzopoulos R, Mayosi BM, McAnulty JH, McDermott MM, McGrath J, Mensah GA, Merriman TR, Michaud C, Miller M, Miller TR, Mock C, Mocumbi AO, Mokdad AA, Moran A, Mulholland K, Nair MN, Naldi L, Narayan KM, Nasseri K, Norman P, O'Donnell M, Omer SB, Ortblad K, Osborne R, Ozgediz D, Pahari B, Pandian JD, Rivero AP, Padilla RP, Perez-Ruiz F, Perico N, Phillips D, Pierce K, Pope CA, Porrini E, Pourmalek F, Raju M, Ranganathan D, Rehm JT, Rein DB, Remuzzi G, Rivara FP, Roberts T, De León FR, Rosenfeld LC, Rushton L, Sacco RL, Salomon JA, Sampson U, Sanman E, Schwebel DC, Segui-Gomez M, Shepard DS, Singh D, Singleton J, Sliwa K, Smith E, Steer A, Taylor JA, Thomas B, Tleyjeh IM, Towbin JA, Truelsen T, Undurraga EA, Venketasubramanian N, Vijayakumar L, Vos T, Wagner GR, Wang M, Wang W, Watt K, Weinstock MA, Weintraub R, Wilkinson JD, Woolf AD, Wulf S, Yeh PH, Yip P, Zabetian A, Zheng ZJ, Lopez AD, Murray CJ, AlMazroa MA, Memish ZA | title = Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010 | journal = Lancet | volume = 380 | issue = 9859 | pages = 2095–128 | date = December 2012 | pmid = 23245604 | doi = 10.1016/S0140-6736(12)61728-0 | pmc = 10790329 | hdl = 10536/DRO/DU:30050819 | s2cid = 1541253 | url = https://zenodo.org/record/2557786 | hdl-access = free | access-date = 14 March 2020 | archive-date = 19 May 2020 | archive-url = https://web.archive.org/web/20200519152712/https://zenodo.org/record/2557786 | url-status = live }}</ref> As of 2018, measles remains a leading cause of vaccine-preventable deaths in the world.<ref name=Kabra2013/><ref>{{cite web |title=Measles Data and Statistics |url=https://www.cdc.gov/measles/downloads/measlesdataandstatsslideset.pdf |access-date=15 August 2019 |archive-date=10 August 2019 |archive-url=https://web.archive.org/web/20190810103234/https://www.cdc.gov/measles/downloads/MeaslesDataAndStatsSlideSet.pdf |url-status=live }}</ref> In developed countries the mortality rate is lower, for example in England and Wales from 2007 to 2017 death occurred between two and three cases out of 10,000.<ref>{{cite web |title=Measles notifications and deaths in England and Wales: 1940 to 2017 |url=https://www.gov.uk/government/publications/measles-deaths-by-age-group-from-1980-to-2013-ons-data/measles-notifications-and-deaths-in-england-and-wales-1940-to-2013 |website=GOV.UK |access-date=1 October 2019 |archive-date=25 July 2019 |archive-url=https://web.archive.org/web/20190725233131/https://www.gov.uk/government/publications/measles-deaths-by-age-group-from-1980-to-2013-ons-data/measles-notifications-and-deaths-in-england-and-wales-1940-to-2013 |url-status=live }}</ref> In children one to three cases out of every 1,000 die in the United States (0.1–0.2%).<ref>{{cite web |url=https://www.cdc.gov/measles/about/complications.html |title=Complications of measles |date=3 November 2014 |publisher=U.S. [[Centers for Disease Control and Prevention]] (CDC) |access-date=7 November 2014 |url-status=live |archive-url=https://web.archive.org/web/20150103130249/http://www.cdc.gov/measles/about/complications.html |archive-date=3 January 2015 }}</ref> In populations with high levels of malnutrition and a lack of adequate healthcare, mortality can be as high as 10%.<ref name=WHO2014/><ref name="Pink Book" /> In cases with complications, the rate may rise to 20–30%.{{medical citation needed|date=November 2019}} In 2012, the number of deaths due to measles was 78% lower than in 2000 due to increased rates of immunization among [[UN member states]].<ref name=Ludlow2015/> Between 2000 and 2016, global cases decreased by 84%; by 2019 cases had increased to a total of 870,000, the highest since 1996.<ref name=":16" />

{| class="wikitable" style="text-align:right; font-size:88%; float:right; clear:right; margin-left:1em"
|+ style="margin-left:1em;" | Reported cases<ref>{{Cite web |title=GHO {{!}} By category {{!}} Measles - Reported cases by WHO region |url=https://apps.who.int/gho/data/view.main.1520_62?lang=en |access-date=6 October 2023 |website=[[World Health Organization]] (WHO) |archive-date=25 November 2023 |archive-url=https://web.archive.org/web/20231125182908/https://apps.who.int/gho/data/view.main.1520_62?lang=en |url-status=live }}</ref>
|-
! WHO-Region
! 1980
! 1990
! 2000
! 2010
! 2020
|-
| align="left" | African Region || 1,240,993 || 481,204 || 520,102 || 199,174 || 115,369
|-
| align="left" | Region of the Americas || 257,790 || 218,579 || 1,754 || 247 || 9,996
|-
| align="left" | Eastern Mediterranean Region || 341,624 || 59,058 || 38,592 || 10,072 || 6,769
|-
| align="left" | European Region || 492,660 || 185,818 || 37,421 || 30,625 || 10,945
|-
| align="left" | Southeast Asia Region || 199,535 || 224,925 || 78,558 || 54,228 || 9,389
|-
| align="left" | Western Pacific Region || 1,319,640 || 155,490 || 177,052 || 49,460 || 6,605
|-
| align="left" | Worldwide || 3,852,242 || 1,325,074 || 853,479 || 343,806 || 159,073
|}

Even in countries where vaccination has been introduced, rates may remain high. Measles is a leading cause of vaccine-preventable childhood mortality. Worldwide, the fatality rate has been significantly reduced by a vaccination campaign led by partners in the [[Measles Initiative]]: the [[American Red Cross]], the United States [[Centers for Disease Control and Prevention|CDC]], the [[United Nations Foundation]], [[UNICEF]] and the WHO. Globally, measles fell 60% from an estimated 873,000 deaths in 1999 to 345,000 in 2005.<ref name="UNICEF">{{cite web|url=http://www.unicef.org/media/media_38076.html|archive-url=https://web.archive.org/web/20150204152400/http://www.unicef.org/media/media_38076.html|url-status=dead|title=UNICEF Joint Press Release|archive-date=4 February 2015}}</ref> Estimates for 2008 indicate deaths fell further to 164,000 globally, with 77% of the remaining measles deaths in 2008 occurring within the Southeast Asian region.<ref>{{cite journal | vauthors = ((World Health Organization)) | title = Global reductions in measles mortality 2000-2008 and the risk of measles resurgence | journal = Weekly Epidemiological Record | volume = 84 | issue = 49 | pages = 509–16 | date = December 2009 | pmid = 19960624 | hdl = 10665/241466 | hdl-access=free }}</ref> There were 142,300 measles related deaths globally in 2018, of which most cases were reported from African and eastern Mediterranean regions. These estimates were slightly higher than that of 2017, when 124,000 deaths were reported due to measles infection globally.<ref name=":9">{{Cite press release|url=https://www.who.int/news-room/detail/05-12-2019-more-than-140-000-die-from-measles-as-cases-surge-worldwide|title=More than 140,000 die from measles as cases surge worldwide|website=[[World Health Organization]] (WHO)|date=5 December 2019|access-date=12 December 2019|archive-date=6 August 2020|archive-url=https://web.archive.org/web/20200806185302/https://www.who.int/news-room/detail/05-12-2019-more-than-140-000-die-from-measles-as-cases-surge-worldwide|url-status=live}}</ref>

In 2000, the WHO established the Global Measles and Rubella Laboratory Network (GMRLN) to provide laboratory surveillance for measles, [[rubella]], and [[congenital rubella syndrome]].<ref name=":7">{{cite journal |last1=Brown |first1=Kevin E. |last2=Rota |first2=Paul A. |last3=Goodson |first3=James L. |last4=Williams |first4=David |last5=Abernathy |first5=Emily |last6=Takeda |first6=Makoto |last7=Mulders |first7=Mick N. |title=Genetic Characterization of Measles and Rubella Viruses Detected Through Global Measles and Rubella Elimination Surveillance, 2016–2018 |journal=MMWR. Morbidity and Mortality Weekly Report |date=5 July 2019 |volume=68 |issue=26 |pages=587–591 |doi=10.15585/mmwr.mm6826a3 |pmid=31269012 |pmc=6613570 }}</ref> Data from 2016 to 2018 show that the most frequently detected measles virus [[genotype]]s are decreasing, suggesting that increasing global population immunity has decreased the number of chains of transmission.<ref name=":7"/>

Cases reported in the first three months of 2019 were 300% higher than in the first three months of 2018, with outbreaks in every region of the world, even in countries with high overall vaccination coverage where it spread among clusters of unvaccinated people.<ref>{{cite press release |title=New measles surveillance data for 2019 |url=https://www.who.int/immunization/newsroom/measles-data-2019/en/ |access-date=4 June 2019 |publisher=[[World Health Organization]] (WHO) |date=15 April 2019 |archive-date=3 June 2019 |archive-url=https://web.archive.org/web/20190603203116/https://www.who.int/immunization/newsroom/measles-data-2019/en/ |url-status=live }}</ref> The numbers of reported cases as of mid-November is over 413,000 globally, with an additional 250,000 cases in DRC (as reported through their national system), similar to the increasing trends of infection reported in the earlier months of 2019, compared to 2018.<ref name=":9"/> In 2019, the total number of cases worldwide climbed to 869,770. The number of cases reported for 2020 is lower compare to 2019.<ref name=":12">{{Cite journal|last1=Patel|first1=Minal K.|last2=Goodson|first2=James L.|last3=Alexander|first3=James P.|last4=Kretsinger|first4=Katrina|last5=Sodha|first5=Samir V.|last6=Steulet|first6=Claudia|last7=Gacic-Dobo|first7=Marta|last8=Rota|first8=Paul A.|last9=McFarland|first9=Jeffrey|last10=Menning|first10=Lisa|last11=Mulders|first11=Mick N.|date=13 November 2020|title=Progress Toward Regional Measles Elimination — Worldwide, 2000–2019|url=http://www.cdc.gov/mmwr/volumes/69/wr/mm6945a6.htm?s_cid=mm6945a6_w|journal=MMWR. Morbidity and Mortality Weekly Report|volume=69|issue=45|pages=1700–1705|doi=10.15585/mmwr.mm6945a6|issn=0149-2195|pmc=7660667|pmid=33180759|access-date=7 December 2020|archive-date=19 March 2023|archive-url=https://web.archive.org/web/20230319203951/http://www.cdc.gov/mmwr/volumes/69/wr/mm6945a6.htm?s_cid=mm6945a6_w|url-status=live}}</ref> According to the WHO, the [[COVID-19 pandemic]] hindered [[Measles vaccination|vaccination campaigns]] in at least 68 countries, including in countries that were experiencing outbreaks, which caused increased risk of additional cases.<ref name=":12"/><ref>{{cite press release | title=At least 80 million children under one at risk of diseases such as diphtheria, measles and polio as COVID-19 disrupts routine vaccination efforts, warn Gavi, WHO and UNICEF | website=[[World Health Organization]] (WHO) | date=22 May 2020 | url=https://www.who.int/news/item/22-05-2020-at-least-80-million-children-under-one-at-risk-of-diseases-such-as-diphtheria-measles-and-polio-as-covid-19-disrupts-routine-vaccination-efforts-warn-gavi-who-and-unicef | access-date=25 June 2022 | archive-date=5 April 2023 | archive-url=https://web.archive.org/web/20230405232933/https://www.who.int/news/item/22-05-2020-at-least-80-million-children-under-one-at-risk-of-diseases-such-as-diphtheria-measles-and-polio-as-Covid-19-disrupts-routine-vaccination-efforts-warn-gavi-who-and-unicef | url-status=live }}</ref>

In 2022, there were an estimated 136,000 measles deaths globally, mostly among unvaccinated or under vaccinated children under the age of 5 years.<ref name="WHO Measles fact sheet">{{Cite web |title=Measles |url=https://www.who.int/news-room/fact-sheets/detail/measles |access-date=30 April 2025 |website=[[World Health Organization]] (WHO) |archive-date=30 April 2025  |archive-url=https://web.archive.org/web/20250430113419/https://www.who.int/news-room/fact-sheets/detail/measles |url-status=live }}</ref>

In February 2024, the World Health Organization said more than half of the world was at risk of a measles outbreak due to COVID-19 pandemic-related disruptions in that month. All the world regions have reported such outbreaks with the exception of the [[Americas]], though these could still be expected to become hotspots in the future. Death rates during the outbreaks tend to be higher among poorer countries but middle-income nations are also heavily impacted, according to the WHO.<ref>{{Cite news |date=21 February 2024 |title=More than half the world faces high measles risk, WHO says |url=https://www.straitstimes.com/world/more-than-half-the-world-faces-high-measles-risk-who-says |access-date=21 February 2024 |work=The Straits Times |issn=0585-3923 |archive-date=21 February 2024 |archive-url=https://web.archive.org/web/20240221045420/https://www.straitstimes.com/world/more-than-half-the-world-faces-high-measles-risk-who-says |url-status=live }}</ref>

In November 2024, the WHO and CDC reported that measles cases increased by 20% in 2023, primarily due to insufficient vaccine coverage in the world's poorest and conflict-affected regions, increasing from about 8.6 to 10.3 million cases.<ref name="MMWR_progress" /><ref name="CNN_cases_surging">{{Cite web |last=Christensen |first=Jen |date=14 November 2024 |title=Measles is debilitating and deadly, and cases are surging, WHO and CDC warn |url=https://www.cnn.com/2024/11/14/health/measles-comeback-who-cdc/index.html |access-date=16 November 2024 |website=CNN }}</ref> Nearly half of the major outbreaks<ref name="CNN_cases_surging" /> and 64% of the individual cases occurred in Africa.<ref name="MMWR_progress">{{Cite journal |last=Minta |first=Anna A. |date=2024 |title=Progress Toward Measles Elimination — Worldwide, 2000–2023 |url=https://www.cdc.gov/mmwr/volumes/73/wr/mm7345a4.htm |journal=MMWR. Morbidity and Mortality Weekly Report |volume=73 |issue=45 |pages=1036–1042 |doi=10.15585/mmwr.mm7345a4 |pmid=39541251 |issn=0149-2195|pmc=11576049 }}</ref>

===Europe===
[[File:Measles in England & Wales1940-2017.png|thumb|350px|Incidence of and deaths due to measles in England and Wales between 1940 and 2017]]
In England and Wales, though deaths from measles were uncommon, they averaged about 500 per year in the 1940s. Deaths diminished with the improvement of medical care in the 1950s, but the incidence of the disease did not retreat until vaccination was introduced in the late 1960s. Wider coverage was achieved in the 1980s with the measles, [[mumps]] and [[rubella]], [[MMR vaccine]].<ref>{{cite web |title=50 years of measles vaccination in the UK |url=https://publichealthengland.exposure.co/50-years-of-measles-vaccination-in-the-uk |website=Public Health England |access-date=15 May 2020 |archive-date=4 November 2020 |archive-url=https://web.archive.org/web/20201104095511/https://publichealthengland.exposure.co/50-years-of-measles-vaccination-in-the-uk |url-status=dead }}</ref>

In 2013–14, there were almost 10,000 cases in 30 European countries. Most cases occurred in unvaccinated individuals and over 90% of cases occurred in Germany, Italy, Netherlands, Romania, and United Kingdom.<ref name=Ludlow2015/> Between October 2014 and March 2015, a measles outbreak in the German capital of [[Berlin]] resulted in at least 782 cases.<ref name="Elizabeth Whitman">{{cite web|url=http://www.ibtimes.com/who-stefan-lanka-court-orders-german-measles-denier-pay-100000-euros-1846078|title=Who Is Stefan Lanka? Court Orders German Measles Denier To Pay 100,000 Euros|author=Elizabeth Whitman|website=[[International Business Times]]|date=13 March 2015|access-date=31 March 2015|url-status=live|archive-url=https://web.archive.org/web/20150402182617/http://www.ibtimes.com/who-stefan-lanka-court-orders-german-measles-denier-pay-100000-euros-1846078|archive-date=2 April 2015}}</ref>

In 2016, a record low of 4,400 cases in Europe were reported. However, from 2017, a [[measles resurgence in Europe]] started to occur with numbers increasing in that year to 21,315 cases, with 35 deaths.<ref>{{cite press release|title=Europe observes a 4-fold increase in measles cases in 2017 compared to previous year|url=http://www.euro.who.int/en/media-centre/sections/press-releases/2018/europe-observes-a-4-fold-increase-in-measles-cases-in-2017-compared-to-previous-year|website=[[World Health Organization]] (WHO)|access-date=22 February 2018|date=19 February 2018|archive-date=21 February 2018|archive-url=https://web.archive.org/web/20180221204224/http://www.euro.who.int/en/media-centre/sections/press-releases/2018/europe-observes-a-4-fold-increase-in-measles-cases-in-2017-compared-to-previous-year|url-status=live}}</ref> In preliminary figures for 2018, reported cases in the region increased 3-fold to 82,596 in 47 countries, with 72 deaths; Ukraine had the most cases (53,218), with the highest incidence rates being in Ukraine (1209 cases per million), Serbia (579), Georgia (564) and Albania (500).<ref>{{cite web |url=http://www.euro.who.int/__data/assets/pdf_file/0004/394060/2019_01_Epi_Data_EN_Jan-Dec-2018.pdf?ua=1 |title=WHO EpiData |publisher=[[World Health Organization]] (WHO) |date=February 2019 |access-date=27 March 2019 |archive-date=29 March 2019 |archive-url=https://web.archive.org/web/20190329133545/http://www.euro.who.int/__data/assets/pdf_file/0004/394060/2019_01_Epi_Data_EN_Jan-Dec-2018.pdf?ua=1 |url-status=live }}</ref><ref name=WHO_Europe_2018_PR>{{cite press release |url=http://www.euro.who.int/en/media-centre/sections/press-releases/2019/measles-in-europe-record-number-of-both-sick-and-immunized |title=Measles in Europe: record number of both sick and immunized |publisher=[[World Health Organization]] (WHO) |date=7 February 2019 |access-date=27 March 2019 |archive-date=10 February 2019 |archive-url=https://web.archive.org/web/20190210022729/http://www.euro.who.int/en/media-centre/sections/press-releases/2019/measles-in-europe-record-number-of-both-sick-and-immunized |url-status=live }}</ref> The previous year (2017) saw an estimated measles vaccine coverage of 95% for the first dose and 90% for the second dose in the region, the latter figure being the highest-ever estimated second-dose coverage.<ref name=WHO_Europe_2018_PR/>

In 2019, the United Kingdom, Albania, the Czech Republic, and Greece lost their measles-free status due to ongoing and prolonged spread of the disease in these countries.<ref name=WJO2019EU>{{cite press release |title=European Region loses ground in effort to eliminate measles |url=http://www.euro.who.int/en/media-centre/sections/press-releases/2019/european-region-loses-ground-in-effort-to-eliminate-measles |website=[[World Health Organization]] (WHO) |access-date=31 August 2019 |date=29 August 2019 |archive-url=https://web.archive.org/web/20200414065648/http://www.euro.who.int/en/media-centre/sections/press-releases/2019/european-region-loses-ground-in-effort-to-eliminate-measles | archive-date=14 April 2020}}</ref> In the first 6 months of 2019, 90,000 cases occurred in Europe.<ref name=WJO2019EU/>

A significant increase in measles cases in Europe occurred in 2024, with 127,350 being reported. This was the highest caseload in the region since 1997, representing a third of global measles cases.
The major centre of the resurgent outbreak appeared to be [[Romania]] where 30,692 cases were reported.<ref name="unicef25">{{cite web |title=European Region reports highest number of measles cases in more than 25 years – UNICEF, WHO/Europe |url=https://www.unicef.org/press-releases/european-region-reports-highest-number-measles-cases-more-25-years-unicef-whoeurope |website=unicef.org |publisher=UNICEF |access-date=15 March 2025 |archive-date=16 March 2025 |archive-url=https://web.archive.org/web/20250316024704/https://www.unicef.org/press-releases/european-region-reports-highest-number-measles-cases-more-25-years-unicef-whoeurope |url-status=live }}</ref>

===Americas===
As a result of widespread vaccination, the disease was declared eliminated from the [[Americas]] in 2016.<ref name=PAHO2016>{{cite web|title=Region of the Americas is declared free of measles|url=https://www.paho.org/hq/index.php?option=com_content&view=article&id=12528:region-americas-declared-free-measles&Itemid=1926&lang=en |website=Pan American Health Organization |access-date=30 September 2016 |date=29 September 2016 |url-status=live |archive-url=https://web.archive.org/web/20160930044745/http://www.paho.org/hq/index.php?option=com_content&view=article&id=12528%3Aregion-americas-declared-free-measles&Itemid=1926&lang=en |archive-date=30 September 2016 }}</ref> However, there were cases again in 2017,<ref>{{cite news |title=Measles spreads again in the Americas |url=https://en.mercopress.com/2018/03/28/measles-spreads-again-in-the-americas |access-date=4 July 2018 |work=MercoPress |date=28 March 2018 |archive-date=4 July 2018 |archive-url=https://web.archive.org/web/20180704182714/http://en.mercopress.com/2018/03/28/measles-spreads-again-in-the-americas |url-status=live }}</ref> 2018, 2019,<ref name="CDC2019"/> and 2020<ref name="CDC Outbreaks"/> in this region.

====United States====
{{see also|Measles resurgence in the United States}}
[[File:Measles US 1938-2019.png|thumb|Measles cases in the U.S. from 1938 to 2019]]
In the United States, measles affected approximately 3,000 people per million in the 1960s before the vaccine was available. With consistent widespread childhood vaccination, this figure fell to 13 cases per million by the 1980s, and to about 1 case per million by 2000.<ref>{{cite journal | vauthors = Orenstein WA, Papania MJ, Wharton ME | title = Measles elimination in the United States | journal = The Journal of Infectious Diseases | volume = 189 | issue = Supplement 1 | pages = S1-3 | date = May 2004 | pmid = 15106120 | doi = 10.1086/377693 | quote = Figure 1: Reported US measles incidence, 1950–2001. | doi-access = free | title-link = doi }}</ref>

In 1991, an [[1990–1991 Philadelphia measles outbreak|outbreak of measles in Philadelphia]] was centered at the Faith Tabernacle Congregation, a faith-healing church that actively discouraged parishioners from vaccinating their children. Over 1400 people were infected with measles and nine children died.<ref>{{cite web|url=https://6abc.com/504818/|title=1991: The Philly measles outbreak that killed 9 children|date=6 February 2015|website=6abc Philadelphia|access-date=7 August 2021|archive-date=25 November 2020|archive-url=https://web.archive.org/web/20201125033257/https://6abc.com/504818/|url-status=live}}</ref>

Before immunization in the United States, between three and four million cases occurred each year.<ref name="Pink Book" /> The United States was declared free of circulating measles in 2000, with 911 cases from 2001 to 2011. In 2014 the CDC said endemic measles, rubella, and [[congenital rubella syndrome]] had not returned to the United States.<ref name=PapaniaSeward2014>{{cite journal | vauthors = Papania MJ, Wallace GS, Rota PA, Icenogle JP, Fiebelkorn AP, Armstrong GL, Reef SE, Redd SB, Abernathy ES, Barskey AE, Hao L, McLean HQ, Rota JS, Bellini WJ, Seward JF | title = Elimination of endemic measles, rubella, and congenital rubella syndrome from the Western hemisphere: the US experience | journal = JAMA Pediatrics | volume = 168 | issue = 2 | pages = 148–55 | date = February 2014 | pmid = 24311021 | doi = 10.1001/jamapediatrics.2013.4342 | doi-access = }}</ref> Occasional measles outbreaks persist, however, because of cases imported from abroad, of which more than half are the result of unvaccinated U.S. residents who are infected abroad and infect others upon return to the United States.<ref name=PapaniaSeward2014/> The CDC continues to recommend measles vaccination throughout the population to prevent outbreaks like these.<ref>{{cite journal | title = Multistate measles outbreak associated with an international youth sporting event--Pennsylvania, Michigan, and Texas, August-September 2007 | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 57 | issue = 7 | pages = 169–73 | date = February 2008 | pmid = 18288074 | url = https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5707a1.htm | author1 = Centers for Disease Control Prevention (CDC) | access-date = 1 February 2018 | archive-date = 18 October 2020 | archive-url = https://web.archive.org/web/20201018010756/https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5707a1.htm | url-status = live }}</ref>

In 2014, an outbreak was initiated in Ohio when two unvaccinated [[Amish]] men harboring asymptomatic measles returned to the United States from missionary work in the Philippines.<ref name="Gastanaduy2016">{{cite journal | vauthors = Gastañaduy PA, Budd J, Fisher N, Redd SB, Fletcher J, Miller J, McFadden DJ, Rota J, Rota PA, Hickman C, Fowler B, Tatham L, Wallace GS, de Fijter S, Parker Fiebelkorn A, DiOrio M | title = A Measles Outbreak in an Underimmunized Amish Community in Ohio | journal = The New England Journal of Medicine | volume = 375 | issue = 14 | pages = 1343–1354 | date = October 2016 | pmid = 27705270 | doi = 10.1056/NEJMoa1602295 | doi-access = free | title-link = doi }}</ref> Their return to a community with low vaccination rates led to an outbreak that rose to include a total of 383 cases across nine counties.<ref name="Gastanaduy2016"/> Of the 383 cases, 340 (89%) occurred in unvaccinated individuals.<ref name="Gastanaduy2016"/>

From 4 January, to 2 April 2015, there were 159 cases of measles reported to the CDC. Of those 159 cases, 111 (70%) were determined to have come from an earlier exposure in late December 2014. This outbreak was believed to have originated from the [[Disneyland]] [[theme park]] in California. The Disneyland outbreak was held responsible for the infection of 147 people in seven U.S. states as well as Mexico and Canada, the majority of which were either unvaccinated or had unknown vaccination status.<ref>{{cite web |url=https://blogs.cdc.gov/publichealthmatters/2015/12/year-in-review-measles-linked-to-disneyland/ |title=Year in Review: Measles Linked to Disneyland |date=2 December 2015 |access-date=26 May 2017 |url-status=live |archive-url=https://web.archive.org/web/20170519211805/https://blogs.cdc.gov/publichealthmatters/2015/12/year-in-review-measles-linked-to-disneyland/ |archive-date=19 May 2017 }}</ref> Of the cases 48% were unvaccinated and 38% were unsure of their vaccination status.<ref>{{cite journal | vauthors = Clemmons NS, Gastanaduy PA, Fiebelkorn AP, Redd SB, Wallace GS | title = Measles - United States, January 4-April 2, 2015 | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 64 | issue = 14 | pages = 373–6 | date = April 2015 | pmid = 25879894 | pmc = 5779542 | url = https://www.cdc.gov/mmwr/pdf/wk/mm6414.pdf | access-date = 1 November 2019 | archive-date = 13 July 2020 | archive-url = https://web.archive.org/web/20200713221937/https://www.cdc.gov/mmwr/pdf/wk/mm6414.pdf | url-status = live }}</ref> The initial exposure to the virus was never identified.<ref>{{cite web|title=Measles Outbreak — California, December 2014–February 2015|url=https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6406a5.htm|access-date=8 January 2022|website=U.S. [[Centers for Disease Control and Prevention]] (CDC)|archive-date=10 December 2020|archive-url=https://web.archive.org/web/20201210053113/https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6406a5.htm|url-status=live}}</ref>

In 2015, a U.S. woman in Washington state died of [[pneumonia]], as a result of measles. She was the first fatality in the U.S. from measles since 2003.<ref>{{cite news |title=Measles kills first patient in 12 years |url=https://www.usatoday.com/story/news/2015/07/02/measles-death-washington-state/29624385/ |access-date=2 July 2015 |newspaper=[[USA Today]] |date=2 July 2015 |url-status=live |archive-url=https://web.archive.org/web/20150702200945/http://www.usatoday.com/story/news/2015/07/02/measles-death-washington-state/29624385/ |archive-date=2 July 2015}}</ref> The woman had been vaccinated for measles and was taking [[immunosuppressive drug]]s for another condition. The drugs suppressed the woman's immunity to measles, and the woman became infected with measles; she did not develop a rash, but contracted pneumonia, which caused her death.<ref>{{cite web |title= First Measles Death in US Since 2003 Highlights the Unknown Vulnerables – Phenomena: Germination |website= [[National Geographic Society]] |url= https://www.nationalgeographic.com/science/phenomena/2015/07/02/measles-death-us/ |access-date= 13 May 2020 |date= 2 July 2015 |archive-date= 31 May 2020 |archive-url= https://web.archive.org/web/20200531020834/https://www.nationalgeographic.com/science/phenomena/2015/07/02/measles-death-us/ |url-status= dead }}</ref><ref>{{cite web |title=First Measles Death In 12 Years Renews Vaccination Concerns |website=[[NPR]] |date=6 July 2015 |url=https://www.npr.org/2015/07/06/420594973/first-measles-death-in-12-years-renews-vaccination-concerns |access-date=23 April 2019 |archive-url= https://web.archive.org/web/20191224204938/https://www.npr.org/2015/07/06/420594973/first-measles-death-in-12-years-renews-vaccination-concerns |archive-date= 24 December 2019}}</ref>

In June 2017, the Maine Health and Environmental Testing Laboratory confirmed a case of measles in Franklin County. This instance marks the first case of measles in 20 years for the state of Maine.<ref>{{cite web|title=Maine confirms its first case of measles in 20 years |url=https://www.cbsnews.com/news/maine-confirms-first-case-measles-20-years/ |website=CBS News |date=27 June 2017 |access-date=28 June 2017 |url-status=live |archive-url=https://web.archive.org/web/20170628021043/http://www.cbsnews.com/news/maine-confirms-first-case-measles-20-years/|archive-date=28 June 2017 }}</ref> In 2018, one case occurred in Portland, Oregon, with 500 people exposed; 40 of them lacked immunity to the virus and were being monitored by county health officials as of 2 July 2018.<ref>{{Cite news|url=http://katu.com/news/local/measles-case-confirmed-in-portland-about-500-people-exposed|title=Measles case confirmed in Portland, about 500 people possibly exposed|work=KATU|access-date=3 July 2018|archive-date=7 August 2020|archive-url=https://web.archive.org/web/20200807014127/https://katu.com/news/local/measles-case-confirmed-in-portland-about-500-people-exposed|url-status=live}}</ref> There were 273 cases of measles reported throughout the United States in 2018,<ref>{{cite web|url=https://wonder.cdc.gov/nndss/static/2018/52/2018-52-table1.html|title=TABLE 1. Weekly cases* of selected infrequently reported notifiable diseases (|website=wonder.cdc.gov|access-date=12 January 2019|archive-date=22 October 2020|archive-url=https://web.archive.org/web/20201022112034/https://wonder.cdc.gov/nndss/static/2018/52/2018-52-table1.html|url-status=live}}</ref> including an outbreak in [[Brooklyn]] with more than 200 reported cases from October 2018 to February 2019. The outbreak was tied with population density of the [[Orthodox Jewish]] community, with the initial exposure from an unvaccinated child that caught measles while visiting Israel.<ref name="usatoday 2019-02-11"/><ref>{{Cite news|url=https://www.cnn.com/2019/01/08/health/measles-outbreak-ny-bn/index.html|title=New York tackles 'largest measles outbreak' in state's recent history as cases spike globally|last=Howard|first=Jacqueline|date=9 January 2019|work=CNN|access-date=12 January 2019|archive-date=11 January 2019|archive-url=https://web.archive.org/web/20190111093850/https://www.cnn.com/2019/01/08/health/measles-outbreak-ny-bn/index.html|url-status=live}}</ref>

A resurgence of measles occurred during 2019, which has been generally tied to [[Vaccine hesitancy|parents choosing not to have their children vaccinated]] as most of the reported cases occurred in people 19 years old or younger.<ref>{{cite web|url=https://www.nbcnews.com/storyline/measles-outbreak/measles-outbreak-southwestern-washington-rises-50-cases-n966751|title=Washington state is averaging more than one measles case per day in 2019|website=NBC News|date=4 February 2019 |access-date=5 February 2019|archive-date=5 February 2019|archive-url=https://web.archive.org/web/20190205011950/https://www.nbcnews.com/storyline/measles-outbreak/measles-outbreak-southwestern-washington-rises-50-cases-n966751|url-status=live}}</ref><ref>{{cite web|url=https://www.msn.com/en-ph/lifestyle/family/amid-measles-outbreak-anti-vaxx-parents-have-put-others-e2-80-99-babies-at-risk/ar-BBTbIBq|title=Amid Measles Outbreak, Anti-Vaxx Parents Have Put Others' Babies At Risk|website=MSN|access-date=5 February 2019|archive-url=https://web.archive.org/web/20190330170245/https://www.msn.com/en-ph/lifestyle/family/amid-measles-outbreak-anti-vaxx-parents-have-put-others-e2-80-99-babies-at-risk/ar-BBTbIBq|archive-date=30 March 2019|url-status=dead}}</ref><ref>{{cite web|url=https://www.vox.com/2019/1/27/18199514/measles-outbreak-2018-clark-county-washington|title=Washington declared a public health emergency over measles. Thank vaccine-refusing parents.|first=Julia|last=Belluz|date=27 January 2019|website=[[Vox (website)|Vox]]|access-date=5 February 2019|archive-date=5 February 2019|archive-url=https://web.archive.org/web/20190205005311/https://www.vox.com/2019/1/27/18199514/measles-outbreak-2018-clark-county-washington|url-status=live}}</ref><ref>{{cite web|url=https://www.newsweek.com/dangerous-anti-vaxx-warning-issued-washington-officials-cases-measles-1306997|title="Dangerous" anti-vaxx warning issued by Washington officials as cases in measles outbreak continue to rise|first=Kashmira|last=Gander|date=28 January 2019|website=[[Newsweek]]|access-date=5 February 2019|archive-date=4 February 2019|archive-url=https://web.archive.org/web/20190204224837/https://www.newsweek.com/dangerous-anti-vaxx-warning-issued-washington-officials-cases-measles-1306997|url-status=live}}</ref><ref name="cnn190424"/> Cases were first reported in Washington state in January, with an [[2019 Pacific Northwest measles outbreak|outbreak of at least 58 confirmed cases]] most within [[Clark County, Washington|Clark County]], which has a higher rate of vaccination exemptions compared to the rest of the state; nearly one in four kindergartners in Clark did not receive vaccinations, according to state data.<ref name="usatoday 2019-02-11">{{cite news | url = https://www.usatoday.com/story/news/health/2019/02/11/measles-spread-anti-vaccination-communities-new-york-clar-county-washington/2812667002/ | title = A quarter of all kindergartners in Washington county aren't immunized. Now there's a measles crisis | first = Ken | last = Alltucker | date = 11 February 2019 | access-date = 11 February 2019 | work = [[USA Today]] | archive-date = 11 February 2019 | archive-url = https://web.archive.org/web/20190211160944/https://www.usatoday.com/story/news/health/2019/02/11/measles-spread-anti-vaccination-communities-new-york-clar-county-washington/2812667002/ | url-status = live }}</ref> This led Washington state governor [[Jay Inslee]] to declare a state of emergency, and the state's congress to introduce legislation to disallow vaccination exemption for personal or philosophical reasons.<ref>{{cite web | url = https://www.seattletimes.com/seattle-news/amid-measles-outbreak-legislation-proposed-to-ban-vaccine-exemptions/ | title = Amid measles outbreak, legislation proposed to ban vaccine exemptions | first = Jake | last = Goldstein-Street | date = 28 January 2019 | access-date = 28 January 2019 | work = [[The Seattle Times]] | archive-date = 29 January 2019 | archive-url = https://web.archive.org/web/20190129011001/https://www.seattletimes.com/seattle-news/amid-measles-outbreak-legislation-proposed-to-ban-vaccine-exemptions/ | url-status = live }}</ref> In April 2019, New York Mayor [[Bill de Blasio]] declared a public health emergency because of "a huge spike" in [[2019 New York measles outbreak|cases of measles]] where there were 285 cases centred on the Orthodox Jewish areas of Brooklyn in 2018, while there were only two cases in 2017. There were 168 more in neighboring [[Rockland County, New York|Rockland County]].<ref>{{cite journal |vauthors=Tanne JH |title=New York City mayor declares measles public health emergency |journal=BMJ |volume=365 |pages=l1724 |date=April 2019 |pmid=30971409 |doi=10.1136/bmj.l1724 |s2cid=145979493 }}</ref> Other outbreaks occurred in Santa Cruz County and Butte County in California, and the states of New Jersey and Michigan.<ref name="cnn190424">{{cite web | url = https://www.cnn.com/2019/04/24/health/measles-outbreak-record-us-bn/index.html | title = US measles outbreak is largest since disease was declared eliminated in 2000 | first1 = Jacqueline | last1 = Howard | first2 = Debra | last2 = Goldschmidt | date = 24 April 2019 | access-date = 24 April 2019 | website = [[CNN]] | archive-date = 24 April 2019 | archive-url = https://web.archive.org/web/20190424160923/https://www.cnn.com/2019/04/24/health/measles-outbreak-record-us-bn/index.html | url-status = live }}</ref> {{As of|April 2019}}, there have been 695 cases of measles reported in 22 states.<ref name="CDC2019"/> {{As of|2019|04}}, this is the highest number of measles cases since measles was declared eliminated in 2000.<ref name="CDC2019">{{cite press release |title=CDC Media Statement: Measles cases in the U.S. are highest since measles was eliminated in 2000 |url=https://archive.cdc.gov/#/details?url=https://www.cdc.gov/media/releases/2019/s0424-highest-measles-cases-since-elimination.html |website=U.S. [[Centers for Disease Control and Prevention]] (CDC) |date=26 April 2019 |access-date=2 May 2019 |archive-date=15 July 2020 |archive-url=https://web.archive.org/web/20200715061619/https://www.cdc.gov/media/releases/2019/s0424-highest-measles-cases-since-elimination.html |url-status=live }}</ref> From January, to December 2019, 1,282 individual cases of measles were confirmed in 31 states.<ref name="CDC Outbreaks">{{cite web | title=Measles Cases and Outbreaks |website=U.S. [[Centers for Disease Control and Prevention]] (CDC) | date=6 January 2020 | url=https://www.cdc.gov/measles/cases-outbreaks.html | archive-url=https://web.archive.org/web/20191101062347/https://www.cdc.gov/measles/cases-outbreaks.html | archive-date=1 November 2019 | url-status=live | access-date=6 January 2020}} {{PD-notice}}</ref> This is the greatest number of cases reported in the US since 1992.<ref name="CDC Outbreaks"/> Of the 1,282 cases, 128 of the people who got measles were hospitalized, and 61 reported having complications, including pneumonia and encephalitis.<ref name="CDC Outbreaks"/> Following the end of the 2019 outbreak, reported cases fell to pre-outbreak levels: 13 cases in 2020, 49 cases in 2021, and 121 cases in 2022.<ref>{{Cite web |date=29 September 2023 |title=Measles Cases and Outbreaks |url=https://www.cdc.gov/measles/data-research/ |access-date=6 October 2023 |website=U.S. [[Centers for Disease Control and Prevention]] (CDC) |archive-date=15 May 2024 |archive-url=https://web.archive.org/web/20240515235451/https://www.cdc.gov/measles/data-research/ |url-status=live }}</ref>

{{As of|2025|02}}, an [[2025 Southwest United States measles outbreak|outbreak of measles]] is ongoing amongst unvaccinated communities in Texas and New Mexico. On 26 February, the first measles death since 2015 was reported to be that of an unvaccinated school-aged child in West Texas. The confirmed number of measles cases in this outbreak is 124 {{as of|2025|02|26|lc=yes}}, according to the Texas Department of Health Services. Most are in children ages 5–17.<ref>{{Cite web |last=Mukherjee |first=Neha |date=26 February 2025 |title=Child in West Texas is first US measles death in a decade |url=https://www.cnn.com/2025/02/26/health/texas-measles-death/index.html |access-date=26 February 2025 |website=CNN }}</ref> As of March 2025, the CDC has recorded 483 confirmed cases across 20 states, 2 deaths and 70 hospitalized. This exceeds the entire 2024 total that was only 285.<ref>{{Cite web |last=IANS |date=29 March 2025 |title=Measles outbreak 2025: US cases surge past 2024 total |url=https://gulfnews.com/world/americas/measles-outbreak-2025-us-cases-surge-past-2024-total-1.500076568 |access-date=30 March 2025 |website=Gulf News }}</ref>

====Brazil====
The spread of measles had been interrupted in Brazil in 2016, with the last-known case twelve months earlier.<ref name="G1-2016">{{cite web|first=Mariana|last=Lenharo|url=http://g1.globo.com/bemestar/noticia/2016/07/sarampo-esta-eliminado-do-brasil-segundo-comite-internacional.html|title=Sarampo está eliminado do Brasil, segundo comitê internacional|publisher=[[G1 (website)|G1]]|date=26 July 2016|access-date=26 July 2016|language=pt|archive-date=27 July 2016|archive-url=https://web.archive.org/web/20160727142754/http://g1.globo.com/bemestar/noticia/2016/07/sarampo-esta-eliminado-do-brasil-segundo-comite-internacional.html|url-status=live}}</ref> This last case was in the state of [[Ceará]].<ref>{{Cite journal|date=26 July 2016|title=Sarampo está eliminado do Brasil, segundo comitê internacional|url=http://g1.globo.com/bemestar/noticia/2016/07/sarampo-esta-eliminado-do-brasil-segundo-comite-internacional.html|journal=Bem Estar|language=pt-BR|access-date=19 December 2018|archive-date=27 July 2016|archive-url=https://web.archive.org/web/20160727142754/http://g1.globo.com/bemestar/noticia/2016/07/sarampo-esta-eliminado-do-brasil-segundo-comite-internacional.html|url-status=live}}</ref>

Brazil won a measles elimination certificate by the [[Pan American Health Organization]] in 2016, but the [[Ministry of Health (Brazil)|Ministry of Health]] has proclaimed that the country has struggled to keep this certificate, since two outbreaks had already been identified in 2018, one in the state of [[Amazonas (Brazilian state)|Amazonas]] and another one in [[Roraima]], in addition to cases in other states ([[Rio de Janeiro (state)|Rio de Janeiro]], [[Rio Grande do Sul]], [[Pará]], [[São Paulo (state)|São Paulo]] and [[Rondônia]]), totaling 1,053 confirmed cases until 1 August 2018.<ref name=":0">{{Cite journal|title=Brasil já tem mais de mil casos de sarampo em 2018, segundo Ministério da Saúde|url=https://g1.globo.com/bemestar/noticia/2018/08/02/brasil-ja-tem-mais-de-mil-casos-de-sarampo-em-2018-segundo-ministerio-da-saude.ghtml|journal=[[G1 (website)|G1]]|date=2 August 2018 |language=pt-BR|access-date=19 December 2018|archive-date=9 November 2020|archive-url=https://web.archive.org/web/20201109021531/https://g1.globo.com/bemestar/noticia/2018/08/02/brasil-ja-tem-mais-de-mil-casos-de-sarampo-em-2018-segundo-ministerio-da-saude.ghtml|url-status=live}}</ref><ref name=":1">{{cite web|url=http://portalms.saude.gov.br/noticias/agencia-saude/43946-ministerio-da-saude-atualiza-casos-de-sarampo-2|title=Ministério da Saúde atualiza casos de sarampo|access-date=2 August 2018|work=portalms.saude.gov.br|last=Saúde|first=Ministério da|language=pt-br|archive-date=20 April 2019|archive-url=https://web.archive.org/web/20190420130416/http://portalms.saude.gov.br/noticias/agencia-saude/43946-ministerio-da-saude-atualiza-casos-de-sarampo-2|url-status=live}}</ref> In these outbreaks, and in most other cases, the contagion was related to the importation of the virus, especially from Venezuela.<ref name=":0"/> This was confirmed by the genotype of the virus (D8) that was identified, which is the same that circulates in Venezuela.<ref name=":1"/>

===Southeast Asia===
In the Vietnamese measles epidemic in spring of 2014, an estimated 8,500 measles cases were reported as of 19 April, with 114 fatalities;<ref>{{cite web|url=http://www.thanhniennews.com/health/vietnam-minister-calls-for-calm-in-face-of-8500-measles-cases-114-fatalities-25423.html|title=Vietnam minister calls for calm in face of 8,500 measles cases, 114 fatalities|author=Lien Chau|publisher=Thanh Niên|date=18 April 2014|access-date=19 April 2014|archive-url=https://web.archive.org/web/20140418220953/http://www.thanhniennews.com/health/vietnam-minister-calls-for-calm-in-face-of-8500-measles-cases-114-fatalities-25423.html|archive-date=18 April 2014|url-status=dead}}</ref> as of 30 May, 21,639 suspected measles cases had been reported, with 142 measles-related fatalities.<ref>{{cite web|url=http://tuoitre.vn/Chinh-tri-Xa-hoi/610133/bo-y-te--vn-da-phan-ung-rat-nhanh-doi-voi-dich-soi.html|title=Bộ Y tế: "VN đã phản ứng rất nhanh đối với dịch sởi"|trans-title=Ministry of Health: "Vietnam has responded very quickly to measles"|author=Quốc Thanh|language=vi|publisher=Tuổi Trẻ|date=30 May 2014|access-date=19 April 2014|archive-url=https://web.archive.org/web/20140531233458/http://tuoitre.vn/Chinh-tri-Xa-hoi/610133/bo-y-te--vn-da-phan-ung-rat-nhanh-doi-voi-dich-soi.html|archive-date=31 May 2014|url-status=live}}</ref> In the [[Naga Self-Administered Zone]] in a remote northern region of [[Myanmar]], at least 40 children died during a measles outbreak in August 2016 that was probably caused by lack of vaccination in an area of poor health infrastructure.<ref>{{cite web|url=https://www.easternmirrornagaland.com/who-doctors-in-myanmars-naga-areas-identify-mystery-disease/|title=WHO doctors in Myanmar's Naga areas identify 'mystery disease'|publisher=Eastern Mirror Nagaland|date=6 August 2016|access-date=8 August 2016|archive-url=https://web.archive.org/web/20170819065303/http://www.easternmirrornagaland.com/who-doctors-in-myanmars-naga-areas-identify-mystery-disease/|archive-date=19 August 2017|url-status=live}}</ref><ref>{{cite web|url=http://www.promedmail.org/post/4398118|title=Myanmar (02): (SA) fatal, measles confirmed|website=www.promedmail.org (Archive Number: 20160806.4398118)|publisher=International Society for Infectious Diseases|access-date=8 August 2016|archive-url=https://web.archive.org/web/20160820090754/http://www.promedmail.org/post/4398118|archive-date=20 August 2016|url-status=dead}}</ref> Following the [[2019 Philippines measles outbreak]], 23,563 measles cases have been reported in the country with 338 fatalities.<ref>{{cite web |url=http://outbreaknewstoday.com/philippines-measles-update-nearly-600-cases-2-days-76902/ |title=Philippines measles update: Nearly 600 cases in 2 days |publisher=Outbreak News Today |date=26 March 2019 |access-date=30 August 2019 |archive-url=https://web.archive.org/web/20190830010007/http://outbreaknewstoday.com/philippines-measles-update-nearly-600-cases-2-days-76902/ |archive-date=30 August 2019 |url-status=live}}</ref> A [[2019 Kuala Koh measles outbreak|measles outbreak]] also happened among the Malaysian [[Orang Asli]] sub-group of [[Batek people]] in the state of [[Kelantan]] from May 2019, causing the deaths of 15 from the tribe.<ref>{{cite web |last=Oon |first=Alyssa J. |date=17 June 2019 |title=A Measles Outbreak Is The Cause of 15 Orang Asli Deaths In Kelantan |url=https://says.com/my/news/mysterious-illness-causing-deaths-of-kampung-kuala-koh-orang-asli-identified-as-measles |url-status=live |archive-url=https://web.archive.org/web/20190827033231/https://says.com/my/news/mysterious-illness-causing-deaths-of-kampung-kuala-koh-orang-asli-identified-as-measles |archive-date=27 August 2019 |access-date=30 August 2019 |publisher=Says.com}}</ref><ref>{{cite web |last=Tay |first=Rachel |date=18 June 2019 |title=The mysterious illness that caused 15 deaths in a Malaysian tribe has been linked to a measles outbreak |work=Business Insider Malaysia |url=https://www.businessinsider.my/the-mysterious-illness-that-caused-15-deaths-in-a-malaysian-tribe-has-been-linked-to-a-measles-outbreak/ |url-status=live |archive-url=https://web.archive.org/web/20190830005853/https://www.businessinsider.my/the-mysterious-illness-that-caused-15-deaths-in-a-malaysian-tribe-has-been-linked-to-a-measles-outbreak/ |archive-date=30 August 2019 |access-date=30 August 2019 }}</ref> In 2024, a measles outbreak was declared in the [[Bangsamoro]] region in the Philippines with at least 592 cases and 3 deaths.<ref>{{cite news |last1=Unson |first1=John |title=Measles outbreak declared in BARMM |url=https://qa.philstar.com/nation/2024/03/24/2342863/measles-outbreak-declared-barmm |access-date=24 March 2024 |work=The Philippine Star |date=24 March 2024}}</ref>

===South Pacific===
A [[2019–2020 New Zealand measles outbreak|measles outbreak in New Zealand]] has 2193 confirmed cases and two deaths. A [[2019 Tonga measles outbreak|measles outbreak in Tonga]] has 612 cases of measles.

==== Samoa ====
A [[2019 Samoa measles outbreak|measles outbreak in Samoa]] in late 2019 has over 5,700 cases of measles and 83 deaths, out of a Samoan population of 200,000. Over three percent of the population were infected, and a state of emergency was declared from 17 November to 7 December. A vaccination campaign brought the measles vaccination rate from 31 to 34% in 2018 to an estimated 94% of the eligible population in December 2019.<ref name="NEOC_R36">{{cite web|url=https://www.facebook.com/samoagovt/posts/2835748539789483|title=National Emergency Operation Centre, update on the measles outbreak: (press release 36) 22 December, 2019|author=Government of Samoa|date=22 December 2019|website=@samoagovt|url-status=live|archive-url=https://archive.today/20200316000531/https://www.facebook.com/samoagovt/posts/2835748539789483|archive-date=16 March 2020|access-date=22 December 2019}}</ref>

===Africa===

The Democratic Republic of the Congo and Madagascar have reported the highest numbers of cases in 2019. However, cases have decreased in Madagascar as a result of nationwide emergency measles vaccine campaigns. As of August 2019 outbreaks were occurring in Angola, Cameroon, Chad, Nigeria, South Sudan and Sudan.<ref>{{cite web|url=https://www.who.int/immunization/newsroom/new-measles-data-august-2019/en/|archive-url=https://web.archive.org/web/20190812222426/https://www.who.int/immunization/newsroom/new-measles-data-august-2019/en/|url-status=dead|archive-date=12 August 2019|title=New measles surveillance data from WHO|website=[[World Health Organization]] (WHO)|access-date=23 November 2019}}</ref>

==== Madagascar ====
An [[2018 Madagascar measles outbreak|outbreak of measles]] in 2018 has resulted in well beyond 115,000 cases and over 1,200 deaths.<ref name="AP">{{cite news|url=https://www.apnews.com/0cd4deb8141742b5903fbef3cb0e8afa|title=Measles outbreak kills more than 1200 in Madagascar|last=Bezain|first=Laetitia|date=14 April 2019|access-date=13 May 2019|publisher=Associated Press}}</ref>

==== Democratic Republic of Congo ====
An [[2019–2020 measles outbreak in the Democratic Republic of the Congo|outbreak of measles]] with nearly 5,000 deaths and 250,000 infections occurred in 2019, after the disease spread to all the provinces in the country.<ref name=BBC2019>{{cite news |url=https://www.bbc.com/news/world-africa-50506743 |title=Nearly 5,000 dead in world's worst measles outbreak |date=21 November 2019 |access-date=23 November 2019 |archive-url=https://web.archive.org/web/20200211233419/https://www.bbc.com/news/world-africa-50506743 |archive-date=11 February 2020}}</ref> Most deaths were among children under five years of age.<ref>{{cite news |url=https://www.theguardian.com/global-development/2019/nov/22/children-bear-the-brunt-as-the-worlds-biggest-measles-epidemic-sweeps-congo |title=Children bear the brunt as the world's biggest measles epidemic sweeps Congo |last=Ratcliffe |first=Rebecca |date=22 November 2019 |work=The Guardian |access-date=23 November 2019 |issn=0261-3077 |archive-url=https://web.archive.org/web/20200507233821/https://www.theguardian.com/global-development/2019/nov/22/children-bear-the-brunt-as-the-worlds-biggest-measles-epidemic-sweeps-congo | archive-date=7 May 2020 }}</ref> The World Health Organization (WHO) has reported this as the world's largest and fastest-moving epidemic.<ref>{{cite web |url=https://www.who.int/immunization/monitoring_surveillance/burden/vpd/surveillance_type/active/measles_monthlydata/en/ |title=Measles and Rubella Surveillance Data |website=[[World Health Organization]] (WHO) |access-date=23 November 2019 |archive-url=https://web.archive.org/web/20200503130400/https://www.who.int/immunization/monitoring_surveillance/burden/vpd/surveillance_type/active/measles_monthlydata/en/ |archive-date=3 May 2020}}</ref>

==History==
[[File:Measles Aztec drawing.jpg|left|thumb|16th-century [[Aztec]] drawing of someone with measles]]
Measles is of [[zoonotic]] origin, having evolved from [[rinderpest]], which infected cattle.<ref name="Furuse2010"/> A precursor of the measles began causing infections in humans as early as the 4th century BC<ref>{{cite journal|last1=Düx|first1=Ariane|last2=Lequime|first2=Sebastian|last3=Patrono|first3=Livia Victoria|last4=Vrancken|first4=Bram|last5=Boral|first5=Sengül|last6=Gogarten|first6=Jan F.|last7=Hilbig|first7=Antonia|last8=Horst|first8=David|last9=Merkel|first9=Kevin|last10=Prepoint|first10=Baptiste|last11=Santibanez|first11=Sabine|date=30 December 2019|title=The history of measles: from a 1912 genome to an antique origin|journal=bioRxiv|pages=2019.12.29.889667|doi=10.1101/2019.12.29.889667| doi-access = free | title-link = doi |last15=Widulin|first20=Philippe|last12=Schlotterbeck|first12=Jasmin|first13=Marc A.|last14=Ulrich|first14=Markus|first21=Sébastien|last21=Calvignac-Spencer|last20=Lemey|first15=Navena|first19=Thomas|last19=Schnalke|first18=Kyle|last18=Harper|first17=Fabian H.|last17=Leendertz|first16=Annette|last16=Mankertz|last13=Suchard}}</ref><ref>{{cite journal|last=Kupferschmidt|first=Kai|date=30 December 2019|title=Measles may have emerged when large cities rose, 1500 years earlier than thought|journal=Science|doi=10.1126/science.aba7352|s2cid=214470603}}</ref> or as late as after 500 AD.<ref name="Furuse2010"/> The [[Antonine Plague]] of 165–180 AD has been speculated to have been measles, but the actual cause of this plague is unknown and smallpox is a more likely cause.<ref>H. Haeser's conclusion, in ''Lehrbuch der Geschichte der Medicin und der epidemischen Krankenheiten'' III:24–33 (1882), followed by Zinsser in 1935.</ref> The first systematic description of measles as distinct from smallpox and [[chickenpox]] is credited to the [[Medicine in medieval Islam|Persian]] physician [[Rhazes|Muhammad ibn Zakariya al-Razi]] (860–932), who published ''The Book of Smallpox and Measles''. He described it as "more to be dreaded than smallpox".<ref name="Pink Book" /><ref>{{cite journal | vauthors = Cohen SG | title = Measles and immunomodulation | journal = The Journal of Allergy and Clinical Immunology | volume = 121 | issue = 2 | pages = 543–4 | date = February 2008 | pmid = 18269930 | doi = 10.1016/j.jaci.2007.12.1152 | url = https://zenodo.org/record/1259085 | access-date = 6 September 2019 | archive-date = 4 December 2020 | archive-url = https://web.archive.org/web/20201204201500/https://zenodo.org/record/1259085 | url-status = live | doi-access = free | title-link = doi }}</ref> It is believed that, at the time of Razi's book, outbreaks were still limited and the virus was not fully adapted to humans. Sometime between 1100 and 1200 AD, the measles virus fully diverged from rinderpest, becoming a distinct virus that infects humans.<ref name = Furuse2010>{{cite journal | vauthors = Furuse Y, Suzuki A, Oshitani H | title = Origin of measles virus: divergence from rinderpest virus between the 11th and 12th centuries | journal = Virology Journal | volume = 7 | pages = 52 | date = March 2010 | pmid = 20202190 | pmc = 2838858 | doi = 10.1186/1743-422X-7-52 | doi-access = free | title-link = doi }}</ref> This agrees with the observation that measles requires a susceptible population of over 500,000 to sustain an epidemic, a situation that occurred in historic times following the growth of medieval European cities.<ref name = Black1966/>

[[File:Hilleman-Walter-Reed.jpeg|thumb|upright=1|[[Maurice Hilleman]]'s measles vaccine is estimated to prevent one million deaths per year.<ref>{{cite news | last=Sullivan | first=Patricia | title=Maurice R. Hilleman Dies; Created Vaccines |newspaper=[[The Washington Post]] | date=13 April 2005 | url=https://www.washingtonpost.com/wp-dyn/articles/A48244-2005Apr12.html | access-date=7 January 2020 | archive-url=https://web.archive.org/web/20121020102622/http://www.washingtonpost.com/wp-dyn/articles/A48244-2005Apr12.html |archive-date=20 October 2012 |url-status=live }}</ref>]]
Measles is an [[endemic disease]], meaning it has been continually present in a community and many people develop resistance. In populations not exposed to measles, exposure to the new disease can be devastating. In 1529, a measles outbreak in [[Cuba]] killed two-thirds of those indigenous people who had previously survived smallpox. Two years later, measles was responsible for the deaths of half the population of [[Honduras]], and it has ravaged [[Mexico]], [[Central America]], and the [[Inca]] civilization.<ref>{{Cite book | first = Joseph Patrick | last = Byrne | title = Encyclopedia of Pestilence, Pandemics, and Plagues: A–M | url = https://books.google.com/books?id=5Pvi-ksuKFIC&pg=PA413 | publisher = ABC-CLIO | year = 2008 | pages = 413 | isbn = 978-0-313-34102-1 | url-status=live | archive-url = https://web.archive.org/web/20131113180934/http://books.google.com/books?id=5Pvi-ksuKFIC&pg=PA413&dq | archive-date = 13 November 2013 }}
</ref>

The 1846 measles outbreak in the [[Faroe Islands]] was unusual for being well studied.<ref name=":2">{{Cite magazine|last=Harper|first=Kyle|date=11 March 2020|title=What Makes Viruses Like COVID-19 Such a Risk for Human Beings? The Answer Goes Back Thousands of Years|url=https://time.com/5800558/coronavirus-human-civilization/|access-date=18 November 2020|magazine=Time|archive-date=7 March 2023|archive-url=https://web.archive.org/web/20230307093708/https://time.com/5800558/coronavirus-human-civilization/|url-status=live}}</ref> Measles had not been seen on the islands for 60 years, so almost no residents had any acquired immunity.<ref name=":2"/> Three-quarters of the residents got sick, and more than 100 (1–2%) died from it before the epidemic burned itself out.<ref name=":2"/> [[Peter Ludvig Panum]] observed the outbreak and determined that measles was spread through direct contact of contagious people with people who had never had measles.<ref name=":2"/> He elucidated the immunity conferred by illness as well as its incubation period by studying this outbreak.<ref name="Pink Book" />

Measles killed 20 percent of [[Hawaii]]'s population in the 1850s.<ref>[https://web.archive.org/web/20090101183418/http://www.digitalhistory.uh.edu/database/article_display.cfm?HHID=422 Migration and Disease]. ''Digital History.''</ref> In 1875, measles killed over 40,000 [[Fiji]]ans, approximately one-third of the population.<ref>{{Cite web |title=Our History |url=http://www.fsm.ac.fj/index.php?option=com_content&view=article&id=114&Itemid=148 |url-status=dead |archive-url=https://web.archive.org/web/20150410002823/http://www.fsm.ac.fj/index.php?option=com_content&view=article&id=114&Itemid=148 |archive-date=10 April 2015 |website=Fiji National University}}</ref> In the 19th century, the disease killed more than half of the [[Great Andamanese]] population.<ref>{{cite news |url=http://news.bbc.co.uk/2/hi/south_asia/4987406.stm |title=Measles hits rare Andaman tribe |first= Subir |last=Bhaumik |archive-url=https://web.archive.org/web/20110823054811/http://news.bbc.co.uk/2/hi/south_asia/4987406.stm |archive-date=23 August 2011 |url-status=live |publisher=[[BBC News Online]] |date=16 May 2006}}</ref>{{Better source needed|date=December 2020}}

In 1914, a statistician for the [[Prudential Insurance Company]] estimated from a survey of 22 countries that 1% of all deaths in the temperate zone were caused by measles. He observed also that 1–6% of cases of measles ended fatally, the difference depending on age (0–3 being the worst), social conditions (e.g. overcrowded tenements) and pre-existing health conditions.<ref>{{cite journal |last=Crum |first=Frederick S |title=A Statistical Study of Measles |journal=American Journal of Public Health |date=April 1914 |volume=IV |issue=4 |pages=289–309 |doi=10.2105/AJPH.4.4.289-a |pmid=18009016 |pmc=1286334 | doi-access = free | title-link = doi }}</ref>

===Vaccination===
{{Main|Measles vaccine}}
Prior to the introduction of vaccines, more than 2 million deaths and 30 million cases were estimated to occur annually around the world.<ref name="Rot2016" /> In 1954, [[John Enders]] and [[Thomas C. Peebles]] isolated the measles virus from a 13-year-old boy from the United States, David Edmonston. Enders was one of the researchers experienced with propagating [[poliovirus]], paving the way for the [[Polio vaccine|Salk vaccine]], and used similar techniques to grow the Edmonston strain in human kidney tissue, then amniotic membrane [[tissue culture]], and finally [[Chicken as biological research model|chick embryo culture]]. This created a virus capable of replicating and generating immunity, but not of causing disease, a process called [[Attenuated vaccine|attenuation]].<ref name="Pink Book" /><ref>{{Cite journal |last=Baker |first=Jeffrey P. |date=1 September 2011 |title=The First Measles Vaccine |url=https://publications.aap.org/pediatrics/article-abstract/128/3/435/30684/The-First-Measles-Vaccine?redirectedFrom=fulltext |journal=Pediatrics |volume=128 |issue=3 |pages=435–437 |doi=10.1542/peds.2011-1430 |pmid=21873696 |issn=0031-4005 |archive-date=18 August 2022 |access-date=21 April 2025 |archive-url=https://web.archive.org/web/20220818112556/https://publications.aap.org/pediatrics/article-abstract/128/3/435/30684/The-First-Measles-Vaccine?redirectedFrom=fulltext |url-status=live |url-access=subscription }}</ref> While at [[Merck & Co.|Merck]], [[Maurice Hilleman]] used the Edmonston B strain to develop the first successful measles vaccine, which became widely available in the United States in 1963.<ref name="Pink Book" /><ref>{{cite journal | title = Measles prevention | journal = MMWR Supplements | volume = 38 | issue = 9 | pages = 1–18 | date = December 1989 | pmid = 2513473 | url = https://www.cdc.gov/mmwr/preview/mmwrhtml/00041753.htm | archive-date = 15 May 2012 | access-date = 10 September 2017 | archive-url = https://web.archive.org/web/20120515055632/http://www.cdc.gov/mmwr/preview/mmwrhtml/00041753.htm | url-status = live | author1 = Centers for Disease Control (CDC) }}</ref><ref>{{cite book |author=Offit PA |title=Vaccinated: One Man's Quest to Defeat the World's Deadliest Diseases |location=Washington, D.C. |publisher=Smithsonian |isbn=978-0-06-122796-7 |year=2007 }}</ref> An improved measles vaccine became available in 1968.<ref>{{cite web |url=http://www.immunize.org/catg.d/p4209.pdf |title=Measles: Questions and Answers |publisher=Immunization Action Coalition |archive-url=https://web.archive.org/web/20130124052237/http://www.immunize.org/catg.d/p4209.pdf |archive-date=24 January 2013 |url-status=unfit}}</ref> The measles vaccine was combined with the [[mumps vaccine]] and [[rubella vaccine]], which are similar [[Attenuated vaccine|live vaccines]] given at the same ages, to create the [[MMR vaccine]]. It was licensed for use in the United States in 1971. The MMR vaccine was combined with the [[varicella vaccine]] to create the [[MMRV vaccine]], which was licensed in 2005.<ref name="Pink Book" />

==Society and culture==
German anti-vaccination campaigner and [[HIV/AIDS denialism|HIV/AIDS denialist]]<ref>{{cite web|url=http://www.virusmyth.com/aids/hiv/slartefact.htm|title=HIV; Reality or artefact?|last=Lanka|first=Stefan|publisher=Virusmyth.com|date=April 1995|access-date=31 March 2015|url-status=dead|archive-url=https://web.archive.org/web/20150326075413/http://www.virusmyth.com/aids/hiv/slartefact.htm|archive-date=26 March 2015|author-link=:de:Stefan Lanka}}</ref> Stefan Lanka posed a challenge on his website in 2011, offering a sum of €100,000 for anyone who could scientifically prove that measles is caused by a virus and determine the diameter of the virus.<ref>{{cite web|url=http://magonia.com/files/stefan-lanka-sarampion.pdf|title=Das Masern-Virus 100.000 € Belohnung! WANTeD Der Durchmesser|language=de|date=24 November 2011|access-date=31 March 2015|url-status=dead|archive-url=https://web.archive.org/web/20150402163126/http://magonia.com/files/stefan-lanka-sarampion.pdf|archive-date=2 April 2015}}</ref> He posited that the illness is [[psychosomatic illness|psychosomatic]] and that the measles virus does not exist. When provided with overwhelming scientific evidence from various medical studies by German physician [[David Bardens]], Lanka did not accept the findings, forcing Bardens to appeal in court. The initial legal case ended with the ruling that Lanka was to pay the prize.<ref name="Elizabeth Whitman"/><ref>{{Cite news|url=https://www.bbc.com/news/world-europe-31864218|title=Germany court orders measles sceptic to pay 100,000 euros|publisher=[[BBC News Online]]|date=12 March 2015|access-date=31 March 2015|url-status=live|archive-url=https://web.archive.org/web/20150331020314/http://www.bbc.com/news/world-europe-31864218|archive-date=31 March 2015}}</ref> However, on appeal, Lanka was ultimately not required to pay the award because the submitted evidence did not meet his exact requirements.<ref>{{cite web|url=http://www.pepijnvanerp.nl/2017/01/disappointing-outcome-of-bardens-vs-lanka-measles-proven-to-exist-but-anti-vaxxer-lanka-keeps-his-money/|title=Disappointing outcome of Bardens vs. Lanka: measles proven to exist, but anti-vaxxer Lanka keeps his money|date=23 January 2017|archive-url=https://web.archive.org/web/20170701211525/http://www.pepijnvanerp.nl/2017/01/disappointing-outcome-of-bardens-vs-lanka-measles-proven-to-exist-but-anti-vaxxer-lanka-keeps-his-money/|archive-date=1 July 2017}}</ref> The case received wide international coverage that prompted many to comment on it, including [[neurologist]], well-known [[skeptic]] and [[science-based medicine]] advocate [[Steven Novella]], who called Lanka "a crank".<ref>{{cite web|url=http://theness.com/neurologicablog/index.php/yes-dr-lanka-measles-is-real/|title=Yes, Dr. Lanka, Measles is Real|last=Novella|first=Steven|publisher=NeuroLogica Blog|date=13 March 2015|access-date=31 March 2015|url-status=dead|archive-url=https://web.archive.org/web/20150331035815/http://theness.com/neurologicablog/index.php/yes-dr-lanka-measles-is-real/|archive-date=31 March 2015|author-link=Steven Novella}}</ref>

As outbreaks easily occur in under-vaccinated populations, the disease is seen as a test of sufficient vaccination within a population.<ref>{{cite book| first1 = Brian Dean | last1 = Abramson | title = Vaccine, Vaccination, and Immunization Law, Third Edition | publisher = [[Bloomberg Law]] | date = 2025 | chapter=Ch. 15-Specific Vaccines | page = 29 | ISBN = 979-8-34170-407-7 }}</ref> Measles outbreaks have been on the rise in the United States, especially in communities with lower rates of vaccination.<ref name="CDC Outbreaks"/> A different vaccine distribution within a single territory by age or social class may define different general perceptions of vaccination efficacy.<ref>{{Cite journal |last=Scirè |first=Giovanni |date=1 January 2021 |title=Modelling and assessing public health policies to counteract Italian measles outbreaks |url=https://www.inderscienceonline.com/doi/abs/10.1504/IJSPM.2021.118832 |journal=International Journal of Simulation and Process Modelling |volume=16 |issue=4 |pages=271–284 |doi=10.1504/IJSPM.2021.118832 |hdl=10447/513505 |issn=1740-2123 |hdl-access=free |access-date=6 May 2022 |archive-date=20 November 2022 |archive-url=https://web.archive.org/web/20221120173734/https://www.inderscienceonline.com/doi/abs/10.1504/IJSPM.2021.118832 |url-status=live }}</ref> It is often introduced to a region by travelers from other countries and it typically spreads to those who have not received the measles vaccination.<ref name="CDC Outbreaks"/>

== References ==
{{Reflist|30em}}

== External links ==
{{sisterlinks|d=Q79793|c=Category:Measles|n=Category:Measles|b=no|v=no|voy=no|m=no|mw=no|s=no|wikt=no|species=no}}
* [https://www.cdc.gov/measles/about/questions.html Questions About Measles] US [[Centers for Disease Control and Prevention]] (CDC)
* [https://www.ema.europa.eu/en/human-regulatory-overview/public-health-threats/vaccine-preventable-diseases-key-facts/measles Measles] [[European Medicines Agency]]
{{Medical condition classification and resources
| ICD11          = {{ICD11|1F03}}
| ICD10          = {{ICD10|B|05||b|00}}
| ICD9           = {{ICD9|055}}
| DiseasesDB     = 7890
| MedlinePlus    = 001569
| eMedicineSubj  = derm
| eMedicineTopic = 259
| eMedicine_mult = {{eMedicine2|emerg|389}} {{eMedicine2|ped|1388}}
| MeshID         = D008457
}}
{{Viral cutaneous conditions}}
{{Diseases of Poverty}}
{{Numbered Diseases of Childhood}}
{{Eradication_of_infectious_disease}}
{{Portal bar|Medicine|Viruses}}
{{Authority control}}

[[Category:Measles| ]]
[[Category:Atypical pneumonias]]
[[Category:Airborne diseases]]
[[Category:Infectious diseases with eradication efforts]]
[[Category:Pediatrics]]
[[Category:Vaccine-preventable diseases]]
[[Category:Virus-related cutaneous conditions]]
[[Category:Wikipedia emergency medicine articles ready to translate]]
[[Category:Wikipedia medicine articles ready to translate]]
[[Category:Articles containing video clips]]