MMR Booster for Adults
Adults born in 1957 or later need at least one dose of MMR vaccine, with a second dose (booster) specifically required for healthcare workers, students in postsecondary educational institutions, and international travelers. 1, 2
Birth Year Determines Baseline Requirements
- Born before 1957: Generally considered immune to measles and mumps without vaccination; however, healthcare facilities should consider vaccinating unvaccinated personnel born before 1957 who lack laboratory evidence of immunity with 2 doses of MMR 1
- Born in 1957 or later: Require documentation of at least 1 dose unless they have laboratory evidence of immunity or medical contraindication 1, 2
Who Needs a Second Dose (Booster)
A routine second MMR dose, administered minimum 28 days after the first dose, is specifically recommended for adults who: 1, 2
- Work in healthcare facilities
- Are students in postsecondary educational institutions (colleges, universities)
- Plan to travel internationally
Additional Booster Indications
Two doses are also required for adults who: 1
- Received inactivated (killed) measles vaccine or measles vaccine of unknown type from 1963-1967
- Were vaccinated before 1979 with killed mumps vaccine or mumps vaccine of unknown type and work in healthcare
- Have been recently exposed to measles or are in an outbreak setting
- Live in a community experiencing a mumps outbreak and are in an affected age group
Special Considerations for Women
For rubella immunity specifically: 1, 2
- All women of childbearing age, regardless of birth year, should have rubella immunity determined
- If no evidence of immunity and not pregnant: vaccinate immediately
- If pregnant without evidence of immunity: administer MMR upon completion or termination of pregnancy before hospital discharge
What Counts as Evidence of Immunity
Acceptable evidence includes: 2, 3
- Documentation of 2 appropriately spaced MMR doses (first dose on or after first birthday)
- Laboratory evidence of immunity to all three diseases
- Laboratory confirmation of disease (provider-diagnosed disease is NOT acceptable for measles, mumps, or rubella) 2, 3
Critical Pitfall
Do not rely on provider-diagnosed disease as evidence of immunity—this was removed from acceptable criteria in 2012 for measles and mumps, and has never been acceptable for rubella 2, 3. Only laboratory-confirmed disease or serologic evidence of immunity counts.
If Serologic Testing Shows No Immunity After 2 Doses
Adults who received 2 documented MMR doses but show negative or equivocal titers do not routinely need additional doses 4. The 2-dose series provides adequate protection even when antibody titers are low or undetectable, as cellular immunity persists. Additional doses beyond the recommended 2-dose series are not routinely indicated outside of outbreak settings 4, 5.
Timing Between Doses
The minimum interval between MMR doses is 28 days 1, 2. There is no maximum interval—if the series is interrupted, continue where you left off without restarting.