From the Guidelines
Adults who need the MMR vaccine should receive two doses, given at least 28 days apart, if they are at higher risk for measles or mumps exposure, such as college students, healthcare workers, international travelers, and people living in communities experiencing an outbreak. This recommendation applies to adults born in 1957 or later who don't have evidence of immunity (such as documentation of vaccination or laboratory evidence of immunity) 1. High-risk groups include:
- College students
- Healthcare workers
- International travelers
- People living in communities experiencing an outbreak Adults born before 1957 are generally considered immune to measles and mumps due to likely childhood exposure and don't routinely need vaccination. The two-dose schedule is important because a single dose provides about 93% protection against measles, while two doses increase effectiveness to approximately 97% 1. For mumps and rubella, two doses also significantly improve immunity compared to a single dose. The MMR vaccine is contraindicated during pregnancy and in severely immunocompromised individuals, but is safe for most adults with no serious side effects beyond temporary soreness at the injection site, mild fever, or rash.
Key considerations for administering two doses of MMR vaccine to adults include:
- A minimum interval of 28 days between doses
- High-risk groups, such as healthcare workers and international travelers, should be prioritized for vaccination
- Adults born before 1957 may not require vaccination due to likely childhood exposure
- The MMR vaccine is contraindicated during pregnancy and in severely immunocompromised individuals 1.
From the Research
Administration of 2 Doses of MMR to Adults
- The Advisory Committee on Immunization Practices (ACIP) recommends 2 doses of MMR vaccine for adults at high risk for exposure and transmission, such as students attending colleges or other post-high school educational institutions, healthcare personnel, and international travelers 2.
- For other adults aged ≥18 years, 1 dose of MMR vaccine is recommended 2.
- A study published in 1989 found that a schedule of two doses of MMR vaccine was helpful in reinforcing immunity in children who did not respond satisfactorily to one dose of MMR 3.
- However, there is limited research on the administration of 2 doses of MMR to adults, and most studies focus on the effectiveness of a third dose of MMR vaccine in controlling mumps outbreaks 4, 5.
- A phase III, randomized study published in 2018 found that a second dose of MMR vaccine administered to healthy participants 7 years of age or older was immunogenic and safe, with comparable reactogenicity profiles to the control vaccine 6.
Special Considerations
- Adults with human immunodeficiency virus (HIV) infection who do not have evidence of current severe immunosuppression should receive 2 doses of MMR vaccine, with revaccination recommended for those who were vaccinated before establishment of effective antiretroviral therapy (ART) 2.
- For prevention of rubella, 1 dose of MMR vaccine is recommended for persons aged ≥12 months 2.
- The ACIP recommendations are reviewed periodically and revised as indicated when new information becomes available 2.