[22] 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.

[23] 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.

A major epidemic was averted due to high rates of vaccination in the surrounding communities.

The US Centers for Disease Control and Prevention recorded 65 affected children in the outbreak by April 2017.

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.

[33] The MMR vaccine is administered by a subcutaneous injection, the first dose typically at twelve months of age.

[40] 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.

[19] The number of reports on neurological disorders is very small, other than evidence for an association between a form of the MMR vaccine containing the Urabe mumps strain and rare adverse events of aseptic meningitis, a form of viral meningitis.

[38][43] 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.

[44] A Cochrane review found that, compared with placebo, MMR vaccine was associated with fewer upper respiratory tract infections, more irritability, and a similar number of other adverse effects.

[17] ITP below the age of six years is generally a mild disease, rarely having long-term consequences.

In 2010, Wakefield's research was found by the General Medical Council to have been "dishonest",[49] and The Lancet fully retracted the paper.

[54] Since Wakefield's publication, multiple peer-reviewed studies have failed to show any association between the vaccine and autism.

Administering the vaccines in three separate doses does not reduce the chance of adverse effects, and it increases the opportunity for infection by the two diseases not immunized against first.

[55][60] Health experts have criticized media reporting of the MMR-autism controversy for triggering a decline in vaccination rates.

[63] The component viral strains of MMR vaccine were developed by propagation in animal and human cells.

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.

[34] Preliminary data indicate a rate of febrile seizures of 9 per 10,000 vaccinations with MMRV, as opposed to 4 per 10,000 for separate MMR and varicella shots; US health officials therefore, do not express a preference for use of MMRV vaccine over separate injections.

[73] In a 2012 study[74] pediatricians and family doctors were sent a survey to gauge their awareness of the increased risk of febrile seizures (fever fits) in the MMRV.

After reading an informational statement only 7% of family doctors and 20% of pediatricians would recommend the MMRV for a healthy 12- to 15-month-old child.

[75] This has caused reduced take-up among some communities,[75][76] despite the fact that alternative vaccines without pig derivatives are approved and available.