The MMR vaccine (abbreviated as MMR) After two doses, 97% of people are protected against measles, 88% against mumps, and at least 97% against rubella. and within 72 hours of exposure to measles among those who are incompletely immunized.
Measles is a highly contagious viral illness that can lead to serious complications, including pneumonia, acute encephalitis, and, in rare cases, long‑term neurological disease. Pregnant women are at increased risk of severe respiratory complications and adverse pregnancy outcomes such as pregnancy loss and premature birth.
The MMR vaccine is widely used around the world. As of 2012, 575 million doses had been administered since the vaccine's introduction worldwide. Measles resulted in 2.6 million deaths per year before immunization became common.
Side effects of immunization are generally mild and resolve without any specific treatment. These may include fever, as well as pain or redness at the injection site. The MMR vaccine is a mixture of live weakened viruses of the three diseases. It was licensed for use in the US by Merck in 1971. Recommendations for a second dose were introduced in 1989.
Medical use
thumb|Priorix
Cochrane concluded that the "Existing evidence on the safety and effectiveness of MMR and MMRV vaccine supports current policies of mass immunisation aimed at global measles eradication to reduce morbidity and mortality associated with measles mumps rubella and varicella."
Measles
upright=1.3|alt=Measles cases 1944-1963 followed a highly variable epidemic pattern, with 150,000-850,000 cases reported per year. A sharp decline followed the introduction of the first measles vaccine in 1963, with fewer than 25,000 cases reported in 1968. Outbreaks around 1971 and 1977 gave 75,000 and 57,000 cases, respectively. Cases were stable at a few thousand per year until an outbreak of 28,000 in 1990. Cases declined from a few hundred per year in the early 1990s to a few dozen in the 2000s. | thumb | Measles cases reported in the [[United States fell drastically after the introduction of the measles vaccine.]]
Before the widespread use of a vaccine against measles, rates of disease were so high that infection was felt to be "as inevitable as death and taxes." Reported cases of measles in the United States fell from hundreds of thousands to tens of thousands per year following introduction of the vaccine in 1963. 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. Fewer than 200 cases have been reported in the US each year between 1997 and 2013, and the disease is no longer considered endemic there.
The benefit of measles vaccination in preventing illness, disability, and death has been well documented. The first 20 years of licensed measles vaccination in the US prevented an estimated 52 million cases of the disease, 17,400 cases of intellectual disability, and 5,200 deaths. During 1999–2004, a strategy led by the World Health Organization and UNICEF led to improvements in measles vaccination coverage that averted an estimated 1.4 million measles deaths worldwide. Between 2000 and 2018, measles vaccination resulted in a 73% decrease in deaths from the disease. This individual returned to a community with many unvaccinated children. The resulting outbreak infected 34 people, mostly children and virtually all unvaccinated; 9% were hospitalized, and the cost of containing the outbreak was estimated at $167,685. A major epidemic was averted due to high rates of vaccination in the surrounding communities.
In 2017, an outbreak of measles occurred among the Somali-American community in Minnesota, where MMR vaccination rates had declined due to the misconception that the vaccine could cause autism. The US Centers for Disease Control and Prevention recorded 65 affected children in the outbreak by April 2017.
Rubella
thumb|upright=1.3|Rubella rates fell sharply in the United States when immunization was introduced.
Rubella, also known as German measles, was also very common before widespread vaccination. The major risk of rubella is during pregnancy when the baby may contract congenital rubella, which can cause significant congenital defects.
Mumps
Mumps is another viral disease that was once very common, especially during childhood. If mumps is acquired by a male who is past puberty, a possible complication is bilateral orchitis, which can in some cases lead to sterility.
Administration
The MMR vaccine is administered by a subcutaneous injection, the first dose typically at twelve months of age. Areas where measles is common typically recommend the first dose at nine months of age and the second dose at fifteen months of age. and 3% develop joint pain lasting 18 days on average. Older women appear to be more at risk of joint pain, acute arthritis, and even (rarely) chronic arthritis. Anaphylaxis is an extremely rare but serious allergic reaction to the vaccine. One cause can be egg allergy. In 2014, the FDA approved two additional possible adverse events on the vaccination label: acute disseminated encephalomyelitis (ADEM), and transverse myelitis, with permission to also add "difficulty walking" to the package inserts. A 2012 IOM report found that the measles component of the MMR vaccine can cause measles inclusion body encephalitis in immunocompromised individuals. This report also rejected any connection between the MMR vaccine and autism. Some versions of the vaccine contain the antibiotic neomycin and therefore should not be used in people allergic to this antibiotic. The UK National Health Service stopped using the Urabe mumps strain in the early 1990s due to cases of transient mild viral meningitis, and switched to a form using the Jeryl Lynn mumps strain instead. The Urabe strain remains in use in a number of countries; MMR with the Urabe strain is much cheaper to manufacture than with the Jeryl Lynn strain, and a strain with higher efficacy along with a somewhat higher rate of mild side effects may still have the advantage of reduced incidence of overall adverse events.
False claims about autism
In 1998 Andrew Wakefield et al. published a <!-- Do not remove the word "fraudulent" without talk page consensus -->fraudulent paper about twelve children, reportedly with bowel symptoms and autism or other disorders acquired soon after administration of MMR vaccine, while supporting a competing vaccine. In 2010, Wakefield's research was found by the General Medical Council to have been "dishonest", and The Lancet fully retracted the paper. Three months following The Lancet's retraction, Wakefield was struck off the UK medical register, with a statement identifying deliberate falsification in the research published in The Lancet, and was barred from practising medicine in the UK. The research was declared fraudulent in 2011 by the British Medical Journal.
Since Wakefield's publication, multiple peer-reviewed studies have failed to show any association between the vaccine and autism. the Institute of Medicine of the US National Academy of Sciences, the UK National Health Service and the Cochrane Library review Health experts have criticized media reporting of the MMR-autism controversy for triggering a decline in vaccination rates. Before publication of Wakefield's article, the inoculation rate for MMR in the UK was 92%; after publication, the rate dropped to below 80%. In 1998, there were 56 measles cases in the UK; by 2008, there were 1348 cases, with two confirmed deaths.
In Japan, the MMR triplet is not used. Immunity is achieved by a combination vaccine for measles and rubella, followed up later with a mumps only vaccine. This has had no effect on autism rates in the country, further disproving the MMR autism hypothesis.
History
thumb|[[Maurice Hilleman, who developed the MMR vaccine]]
thumb|Two workers make openings in chicken eggs in preparation for a measles vaccine.
The component viral strains of MMR vaccine were developed by propagation in animal and human cells.
For example, in the case of mumps and measles viruses, the virus strains were grown in embryonated chicken eggs. This produced strains of virus which were adapted for chicken cells and less well-suited for human cells. These strains are therefore called attenuated strains. They are sometimes referred to as neuroattenuated because these strains are less virulent to human neurons than the wild strains.
The rubella component, Meruvax, was developed in 1967, through propagation using the human embryonic lung cell line WI-38 (named for the Wistar Institute) that was derived six years earlier in 1961.
{| class="wikitable"
!Disease immunized
!Component vaccine
!Virus strain
!Propagation medium
!Growth medium
|-
|Measles
|Attenuvax
| Enders' attenuated Edmonston strain
| rowspan="2"|chick embryo cell culture
| rowspan="2" |Medium 199
|-
|Mumps
|Mumpsvax
|Jeryl Lynn (B level) strain
|-
|Rubella
|Meruvax II
| Wistar RA 27/3 strain of live attenuated rubella virus
| WI-38 human embryonic cell line
| MEM (solution containing buffered salts, fetal bovine serum, human serum albumin and neomycin, etc.)
|}
The term "MPR vaccine" is also used to refer to this vaccine, whereas "P" refers to parotitis which is caused by mumps.
According to a review published in 2018, the GlaxoSmithKline (GSK) MMR vaccine known as Pluserix "contains the Schwarz measles virus, the Jeryl Lynn–like mumps strain, and RA27/3 rubella virus".
Pluserix was introduced in Hungary in 1999. GSK Priorix vaccine, which uses attenuated Schwarz Measles, was introduced in Hungary in 2003.
MR vaccine
The MR vaccine (abbreviated "MRV") is a vaccine for measles and rubella, not mumps.
Society and culture
Religious concerns
Some brands of the vaccine use gelatin, derived from pigs, as a stabilizer. despite the fact that alternative vaccines without pig derivatives are approved and available.