MMR Vaccine Schedule and Administration Recommendations
The recommended MMR vaccine schedule includes two doses: the first dose at 12-15 months of age and the second dose at 4-6 years of age (before school entry). 1, 2
First Dose Recommendations
- The first dose of MMR vaccine should be administered between 12-15 months of age as part of routine childhood immunization 1, 3
- The minimum age for MMR vaccination is 12 months 1
- For children who missed the routine schedule, the first dose can be administered up to 12 years of age 1
- Studies show that children vaccinated at 12 months of age have a 93-96% seroconversion rate compared to 98% at 15 months, but this slight difference has limited clinical importance since a second dose is recommended for all children 3
- Earlier administration at 12 months (versus 15 months) can improve vaccination coverage 3
Second Dose Recommendations
- The second dose is routinely recommended at age 4-6 years before school entry 1, 3
- The second dose may be administered earlier than 4-6 years, provided at least 4 weeks (28 days) have elapsed since the first dose 1, 3
- The second dose serves primarily to immunize children who failed to respond to the first dose rather than to boost waning immunity 3
- Some states may have specific school entry requirements for the second dose at either kindergarten entry (4-6 years) or middle school entry (11-12 years) 3
Administration Options
- For the first dose in children aged 12-47 months, either:
- When considering MMRV for the first dose in children 12-47 months, providers should discuss benefits and risks with parents/caregivers, noting that MMRV is associated with a higher risk of fever and febrile seizures compared to separate MMR and varicella vaccines 3
- Unless the parent specifically requests MMRV, the CDC recommends using separate MMR and varicella vaccines for the first dose in children 12-47 months 3
- For the second dose at any age (15 months-12 years), MMRV vaccine is generally preferred over separate injections 3, 1
Special Populations
Adults
- Adults born in 1957 or later without evidence of immunity should receive at least one dose of MMR vaccine 3
- Two doses of MMR vaccine are recommended for:
- Students in post-high school educational institutions
- Healthcare personnel
- International travelers 2
- Women of childbearing age should receive at least one dose of MMR or other live rubella virus vaccine unless they have serologic evidence of immunity 3
Immunocompromised Individuals
- A personal or family history (sibling or parent) of seizures of any etiology is a precaution for MMRV vaccination; in these cases, separate MMR and varicella vaccines are recommended 3, 1
- Persons with HIV infection who do not have evidence of severe immunosuppression should receive MMR vaccination 2
Minimum Intervals and Coadministration
- The minimum interval between the first and second doses of MMR vaccine is 28 days (4 weeks) 1, 3
- MMR vaccine may be administered simultaneously with other vaccines 1
- If not administered simultaneously with other live vaccines, MMR should be given at least 28 days before or after another live vaccine 1
Efficacy and Immunogenicity
- Studies show high seroconversion rates (92-100%) after MMR vaccination in both age groups (9-10 months and 15-18 months) 4
- Antibody persistence studies show that while measles antibodies remain relatively stable, rubella antibody levels may decline by ages 11-13 years, though this is addressed by the second dose 5
- A second dose of MMR vaccine induces robust immune responses in individuals aged 7 years or older who had received at least one previous dose 6
The two-dose MMR schedule provides excellent protection against measles, mumps, and rubella, with the timing designed to maximize immune response while ensuring protection before school entry when exposure risk increases.