Measles vaccine protects against becoming infected withmeasles.[1] Nearly all of those who do not develop immunity after a single dose develop it after a second dose.[1] When the rate ofvaccination within apopulation is greater than 92%,outbreaks of measles typically no longer occur; however, they may occur again if the rate of vaccination decreases.[1] Thevaccine's effectiveness lasts many years.[1] It is unclear if it becomes less effective over time.[1] The vaccine may also protect against measles if given within a couple of days after exposure to measles.[2][1][3][4]
The vaccine is generally safe, even for those infected byHIV.[1][5] Most children do not experience any side effects;[6] those that do occur are usually mild (such as fever, rash, pain at the site of injection, and joint stiffness) and short-lived.[1][6]Anaphylaxis has been documented in about 3.5–10 cases per million doses.[1] Rates ofGuillain–Barré syndrome,autism andinflammatory bowel disease do not appear to be increased by measles vaccination.[1][7]
The vaccine is available bothby itself and in combinations such as theMMR vaccine (a combination with therubella vaccine andmumps vaccine)[1] or theMMRV vaccine (a combination of MMR with thechickenpox vaccine).[8][9][10] The measles vaccine is equally effective for preventing measles in all formulations, but side effects vary for different combinations.[1][11] TheWorld Health Organization (WHO) recommends measles vaccine be given at nine months of age in areas of the world where the disease is common, or at twelve months where the disease is not common.[12][1] Measles vaccine isbased on a live but weakened strain of measles.[1] It comes as a dried powder that is mixed with aspecific liquid before being injected either just under the skin or into a muscle.[1] Verification that the vaccine was effective can be determined by blood tests.[1]
The measles vaccine was first introduced in 1963.[13] In that year, the Edmonston-B strain of measles virus was turned into a vaccine byJohn Enders and colleagues and licensed in the United States.[14][15] In 1968, an improved and even weaker measles vaccine was developed byMaurice Hilleman and colleagues, and began to be distributed, becoming the only measles vaccine used in the United States since 1968.[16][14][15] About 86% of children globally had received at least one dose of the vaccine as of 2018.[17] In 2021, at least 183 countries provided two doses in their routine immunization schedule.[18] It is on theWorld Health Organization's List of Essential Medicines.[19] As outbreaks easily occur in under-vaccinated populations, non-prevalence of disease is seen as a test of sufficient vaccination within a population.[20][21]
Measles cases reported in the United States before and after the introduction of the vaccineMeasles cases reported in Canada before and after introduction of the vaccine. Between 1959 and 1968 measles was not nationally reportable, hence there are no data are this period.Measles cases reported in England andWales
One dose is about 93% effective while two doses of the vaccine are about 97% effective at preventing measles.[5] Before the widespread use of the vaccine, measles was so common that infection was considered "as inevitable as death and taxes."[22] In the United States, reported cases of measles fell from 3 to 4 million with 400 to 500 deaths to tens of thousands of cases per year following introduction of two measles vaccines in 1963 (both an inactivated and a liveattenuated vaccine (Edmonston B strain) were licensed for use, see chart at right).[5][23] Increasing uptake of the vaccine following outbreaks in 1971 and 1977 brought this down to thousands of cases per year in the 1980s. An outbreak of almost 30,000 cases in 1990 led to a renewed push for vaccination and the addition of a second vaccine to the recommended schedule. No more than 220 cases were reported in any year from 1997 to 2013, and the disease was believed no longerendemic in the United States.[24][25][26] In 2014, 667 cases were reported.[27]
The benefits of measles vaccination in preventing illness, disability, and death have been well documented. Within the first 20 years of being licensed in the U.S., measles vaccination prevented an estimated 52 million cases of the disease, 17,400 cases ofintellectual disability, and 5,200 deaths.[28] From 1999 to 2004 a strategy led by the WHO andUNICEF led to improvements in measles vaccination coverage that averted an estimated 1.4 million measles deaths worldwide.[29] The vaccine for measles led to the near-complete elimination of the disease in the United States and other developed countries.[30] While the vaccine is made with a live virus which can cause side effects, these are far fewer and less serious than the sickness and death caused by measles itself; side effects ranging from rashes to, rarely,convulsions, occur in a small percentage of recipients.[31]
Measles iscommon worldwide. Although it was declared eliminated from the U.S. in 2000, high rates of vaccination and excellent communication with those who refuse vaccination are needed to prevent outbreaks and sustain the elimination of measles.[33] Of the 66 cases of measles reported in the U.S. in 2005, slightly over half were attributable to one unvaccinated teenager who became infected during a visit to Romania.[34] This individual returned to a community with many unvaccinated children. The resulting outbreak infected 34 people, mostly children and virtually all unvaccinated; three of them were hospitalized. The public health response required making almost 5,000 phone calls as part ofcontact tracing, arranging and performing testing as needed, and arranging emergency vaccination for at-risk people who had had contact with this person.[33] Taxpayers and local healthcare organizations likely paid more than US$167,000 in direct costs to contain this one outbreak.[33] A majorepidemic was averted due to high rates of vaccination in the surrounding communities.[33]
When addressing the major U.S. measles outbreak in 2019, theCenters for Disease Control and Prevention stated that outbreaks are more likely in areas with pockets of unvaccinated residents.[35] However, during the U.S. outbreak beginning in February 2025, the agency declined to publicize their updated expert assessment and forecasting model supporting this conclusion, thereby choosing not to alert clinicians and the public of being at specific risk in areas with low immunization rates.[36]
The vaccine has nonspecific effects such as preventing respiratory infections, that may be greater than those of measles prevention alone.[37] These benefits are greater when the vaccine is given before one year of age.[38] A high-titre vaccine resulted in worse outcomes in girls, and consequently is not recommended by the World Health Organization.[39]
The immune response to the measles vaccine can be impaired by the presence of parasitic infections such ashelminthiasis.[40]
TheWorld Health Organization (WHO) recommends two doses of vaccine for all children.[1] In countries with a high risk of disease the first dose should be given around nine months of age.[1] Otherwise it can be given at twelve months of age.[1] The second dose should be given at least one month after the first dose.[1] This is often done at age 15 to 18 months.[1] After one dose at the age of nine months 85% are immune, while a dose at twelve months results in 95% immunity.[13]
In the United States, theCenters for Disease Control and Prevention (CDC) recommends that children aged six to eleven months traveling outside the United States receive their first dose of MMR vaccine before departure[41] and then receive two more doses; one at 12–15 months (12 months for children in high-risk areas) and the second as early as four weeks later.[42] Otherwise the first dose is typically given at 12–15 months and the second at 4–6 years.[42]
In the UK, theNational Health Service (NHS) recommendation is for a first dose at around 13 months of age and the second at three years and four months old.[43][44]
In Canada,Health Canada recommends that children traveling outside North America should receive anMMR vaccine if they are aged six to 12 months. However, after the child is 12 months old they should receive two additional doses to ensure long-lasting protection.[45]
Adverse effects associated with the MMR vaccine includefever, rash, injection site pain, and, in rare cases, red or purple discolorations on the skin known asthrombocytopenic purpura, or seizures related to fever (febrile seizure).[46][47]
In 1998,Andrew Wakefield et al. published a now retracted and fraudulentThe Lancet paper linking theMMR vaccine to autism, leading to a decline in vaccination rates.[48][49][50] Wakefield was later found to have been "dishonest" by theGeneral Medical Council and barred from practicing medicine in the UK.[51] Numerous subsequent studies and reviews by organizations such as the USCenters for Disease Control and Prevention,Institute of Medicine,NHS and theCochrane Library have found no evidence of a link between the MMR vaccine and autism.[52][53][54] The controversy surrounding Wakefield's publication led to decreased MMR vaccination rates and a subsequent increase in measles cases in the UK.[55] In Japan, where the MMR vaccine is not used as a combined vaccine, autism rates have remained unaffected, further disproving Wakefield's hypothesis.[56]
According to a 2019Los Angeles Times article, concerns were raised about unvaccinated students contributing to the large number of measles outbreaks.[57]
Some people shouldn't receive the measles or MMR vaccine, including cases of:
Pregnancy: MMR vaccine and its components should not be given to pregnant women.[61] Women of childbearing age should check with their doctor about getting vaccinated prior to getting pregnant.[10]
HIV-infected children, who may receive measles vaccines if theirCD4+ lymphocyte count is greater than 15%.[62]
Weakened immune system due to HIV/AIDS or certain medical treatments[10]
Having a parent or sibling with a history of immune problems[10]
Condition that makes a patient bruise or bleed easily[10]
Number of one-year olds who have received measles vaccinations over time[63]Cases of measles and deaths per 100000, per year, in the United States over the 20th century
John Franklin Enders, who had shared the 1954Nobel Prize in Medicine for work on the polio virus, sentThomas C. Peebles toFay School in Massachusetts, where an outbreak of measles was underway. Peebles was able to isolate the virus from blood samples and throat swabs. He later successfully cultivated the virus and showed that the disease could be passed on to monkeys inoculated with the material he had collected.[30] Enders used the cultivated virus to develop a measles vaccine in 1963 by attenuation through cultured chicken embryo fibroblasts of the material isolated by Peebles.[64][65]
In the late 1950s and early 1960s, nearly twice as many children died from measles as from polio.[66] The vaccine Enders developed was based on the Edmonston strain of attenuated live measles virus, which was named for 11-year-old David Edmonston, the Fay student from whom Peebles had taken the culture that led to the virus's cultivation.[67]
In the mid-20th century, measles was particularly devastating in West Africa, where child mortality rate was 50 percent before age five, and the children were struck with the type of rash and other symptoms common prior to 1900 in England and other countries.[citation needed] The first trial of a live attenuated measles vaccine was undertaken in 1960 by the British paediatricianDavid Morley in a village nearIlesha, Nigeria;[68] in case he could be accused of exploiting the Nigerian population, Morley included his own four children in the study. The encouraging results led to a second study of about 450 children in the village and at the Wesley Guild Hospital in Ilesha.[citation needed]
Following another epidemic, a larger trial was undertaken in September and October 1962, in New York City with the assistance of the WHO: 131 children received the live Enders-attenuated Edmonston B strain plusgamma globulin, 130 children received a "further attenuated" vaccine without gamma globulin, and 173 children acted as control subjects for both groups. As also shown in the Nigerian trial, the trial confirmed that the "further attenuated" vaccine was superior to the Edmonston B vaccine, and caused significantly fewer instances of fever and diarrhea. 2,000 children in the area were vaccinated with the further-attenuated vaccine.[69][70]
Maurice Hilleman atMerck & Co., a pioneer in the development of vaccinations, developed an improved version of the measles vaccine in 1968 and subsequently theMMR vaccine in 1971, which vaccinates against measles,mumps andrubella in a single shot followed by a booster.[14][31][71] One form is called "Attenuvax".[72] The measles component of the MMR vaccine uses Attenuvax,[73] which is grown in a chick embryo cell culture using the Enders' attenuated Edmonston strain.[73] FollowingACIP recommendations, Merck decided not to resume production of Attenuvax as standalone vaccine on 21 October 2009.[74]
A 2022 study in theAmerican Economic Journal found that the measles vaccine uptake led to increases in income of 1.1 percent and positive effects on employment due to greater productivity by those who were vaccinated.[75]
Mumps, measles and rubella combined vaccine (MMR vaccine)
Measles is seldom given as an individual vaccine and is often given in combination withrubella,mumps, orvaricella (chickenpox) vaccines.[1]Below is the list of measles-containing vaccines:
Most health insurance plans in the United States cover the cost of vaccines, andVaccines for Children Program may be able to help those who do not have coverage.[78] State law requires vaccinations for school children, but offer exemptions for medical reasons and sometimes for religious or philosophical reasons.[79] All fifty states require two doses of the MMR vaccine at the appropriate age.[80] A different vaccine distribution within a single territory by age or social class may define different general perceptions of vaccination efficacy.[81]
^abCDC (2 August 2019)."Measles and the Vaccine (Shot)".Centers for Disease Control and Prevention.Archived from the original on 29 January 2020. Retrieved30 April 2020.
^abcCDC (5 November 2020)."History of Measles".Centers for Disease Control and Prevention.Archived from the original on 6 April 2020. Retrieved9 February 2021.
^World Health Organization (2025).The selection and use of essential medicines, 2025: WHO Model List of Essential Medicines, 24th list. Geneva: World Health Organization.doi:10.2471/B09474.hdl:10665/382243. License: CC BY-NC-SA 3.0 IGO.
^"Measles".www.who.int.Archived from the original on 1 June 2019. Retrieved28 April 2022.
^Abramson BD (2025). "Ch. 15-Specific Vaccines".Vaccine, Vaccination, and Immunization Law, Third Edition.Bloomberg Law. p. 29.ISBN979-8-34170-407-7.
^Wallace G, Leroy Z (2015)."Measles". In Hamborsky J, Kroger A, Wolfe S (eds.).Epidemiology and Prevention of Vaccine-Preventable Diseases (13th ed.). Washington D.C.: Public Health Foundation.Archived from the original on 7 February 2015. Retrieved30 April 2019.
^Centers for Disease Control and Prevention (CDC) (December 2006)."Measles--United States, 2005".MMWR. Morbidity and Mortality Weekly Report.55 (50):1348–51.PMID17183226.Archived from the original on 13 March 2015.
^Mina MJ (June 2017). "Measles, immune suppression and vaccination: direct and indirect nonspecific vaccine benefits".The Journal of Infection.74 (Suppl 1):S10–S17.doi:10.1016/S0163-4453(17)30185-8.PMID28646947.
^The Editors of The Lancet (February 2010). "Retraction—Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children".Lancet.375 (9713): 445.doi:10.1016/S0140-6736(10)60175-4.PMID20137807.S2CID26364726.
^"Contraindications and Precautions".Vaccine Recommendations and Guidelines of the ACIP. Centers for Disease Control and Prevention. 23 April 2020.Archived from the original on 1 May 2019. Retrieved30 April 2019.
^Ovsyannikova IG, Johnson KL, Naylor S, Poland GA (February 2005). "Identification of HLA-DRB1-bound self-peptides following measles virus infection".Journal of Immunological Methods.297 (1–2):153–67.doi:10.1016/j.jim.2004.12.020.PMID15777939.
.jpg)
N
Y (what is this?) (verify)
This article incorporates text from this source, which is in thepublic domain.
