Ask the Experts: MMR (Measles, Mumps, and Rubella): Vaccine Safety

Results (4)

No. This issue has been studied extensively, including a thorough review by the independent Institute of Medicine (IOM). The IOM issued a report in 2004 that concluded there is no evidence supporting an association between MMR vaccine or thimerosal-containing vaccines and the development of autism. For more information on thimerosal and vaccines in general, visit

Last reviewed: June 19, 2023

Merck no longer produces single antigen measles, mumps, and/or rubella vaccines for the U.S. market. Only combined MMR is available. You should educate parents about the lack of association between MMR and autism. You may provide parents with’s parent handout (developed in collaboration with the Autism Science Foundation): Evidence Shows Vaccines Unrelated to Autism, found at

Last reviewed: June 19, 2023

Arthralgia (joint pain) and transient arthritis (joint redness or swelling) following rubella vaccination occurs only in people who were susceptible to rubella at the time of vaccination. Joint symptoms are uncommon in children and in adult biological males. About 25% of non-immune post-pubertal biological females report joint pain after receiving rubella vaccine, and about 10% to 30% report arthritis-like signs and symptoms.

When joint symptoms occur, they generally begin 1 to 3 weeks after vaccination, usually are mild and not incapacitating, last about 2 days, and rarely recur.

Last reviewed: June 19, 2023

In general, although it is not ideal, receiving extra doses of vaccine poses no medical problem. However, receiving excessive doses of tetanus toxoid (e.g., DTaP, DT, Tdap, or Td) can increase the risk of a local adverse reaction. For details see the Extra Doses of Vaccine Antigens section of the ACIP “General Best Practice Guidelines for Immunization” at

Vaccination providers frequently encounter people who do not have adequate documentation of vaccinations. Providers should only accept written, dated records as evidence of vaccination. With the exception of influenza vaccine and pneumococcal polysaccharide vaccine, self-reported doses of vaccine without written documentation should not be accepted. An attempt to locate missing records should be made whenever possible by contacting previous healthcare providers, reviewing state or local immunization information systems, and searching for a personally held record.

If records cannot be located or will definitely not be available anywhere because of the patient’s circumstances, children without adequate documentation should be considered susceptible and should receive age-appropriate vaccination. Serologic testing for immunity is an alternative to vaccination for certain antigens (e.g., measles, rubella, hepatitis A, diphtheria, and tetanus).

Last reviewed: June 19, 2023

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