What is the recommended administration schedule and contraindications for the Measles, Mumps, and Rubella (MMR) vaccine in pediatric and adult patients?

MMR Vaccine: Administration Schedule and Contraindications

All children should receive two doses of MMR vaccine: the first dose at 12-15 months of age and the second dose at 4-6 years of age before school entry, with a minimum interval of 4 weeks between doses. 1, 2

Pediatric Vaccination Schedule

First Dose Timing

• Administer the first dose at 12-15 months of age as part of routine childhood immunization 3, 1, 2
• The minimum age for MMR vaccination is 12 months 1
• In high-risk areas (large inner city populations, recent outbreaks, or >5 cases among preschoolers in the last 5 years), administer as early as 12 months 3

Second Dose Timing

• Routinely administer the second dose at 4-6 years of age (before kindergarten or first grade entry) 3, 1, 2
• The second dose may be given earlier than 4 years, provided at least 4 weeks have elapsed since the first dose 1, 2
• This timing was jointly adopted by ACIP, AAP, and AAFP to reduce primary vaccine failure, which occurs in approximately 5% of children receiving only one dose 3

Catch-Up Vaccination

• Children who missed their scheduled doses should receive 2 doses with a minimum 4-week interval, regardless of current age or time elapsed 1
• Never restart the vaccine series—continue where you left off 1
• For adolescents aged 11-12 years without documentation of two doses, administer MMR vaccine during the routine health maintenance visit 3

Adult Vaccination

General Adult Recommendations

• Adults born in 1957 or later without documentation of vaccination or immunity should receive at least one dose of MMR vaccine 2
• Most persons born before 1957 are presumed immune due to natural infection, though this does not guarantee immunity 3

High-Risk Adults Requiring Two Doses

• Students attending colleges or post-high school educational institutions 4, 5
• Healthcare personnel 4, 5
• International travelers 4

MMRV Combination Vaccine Considerations

First Dose (Ages 12-47 Months)

• Use separate MMR and varicella vaccines rather than MMRV for the first dose in children 12-47 months due to increased febrile seizure risk 1, 2
• MMRV carries approximately one additional febrile seizure per 2,300-2,600 doses compared to separate vaccines in children aged 12-23 months 1
• Either MMR plus separate varicella or MMRV may be used, but providers must discuss the increased seizure risk with parents/caregivers 1

Second Dose (Any Age)

• MMRV is generally preferred over separate injections for the second dose at any age (15 months-12 years) 1, 2
• For first doses at ≥48 months, MMRV is also preferred (the 47-month cutoff was selected because approximately 97% of febrile seizures occur in children ≤47 months) 1

Seizure History Precaution

• A personal or family history (sibling or parent) of seizures of any etiology is a precaution for MMRV vaccination 1, 2
• In these cases, use separate MMR and varicella vaccines instead 1, 2

Key Contraindications

Absolute Contraindications

• Severe immunocompromise (MMR should not be administered to severely immunocompromised children) 1, 2
• Pregnancy 2
• Severe anaphylactic reaction to vaccine components 2
• High-dose systemic corticosteroids 2

Special Populations

HIV-Infected Children

• HIV-infected children should receive MMR vaccine at 12 months if not severely immunosuppressed 3
• Asymptomatic HIV-infected children without severe immunosuppression should receive MMR as soon as possible upon reaching 12 months, and consider the second dose as early as 28 days after the first 1
• Children with perinatal HIV infection who were vaccinated before effective antiretroviral therapy (ART) should be revaccinated with 2 appropriately spaced doses once effective ART is established 4

Administration Guidelines

Timing with Other Vaccines

• MMR may be administered simultaneously with other vaccines 2
• If not given simultaneously with other live vaccines, administer at least 28 days before or after another live vaccine 2
• For varicella vaccine specifically, a minimum interval of 3 months is recommended when not given simultaneously 2

Minimum Intervals

• The minimum interval between first and second MMR doses is 4 weeks 1, 2
• For varicella vaccine in children 12 months-12 years, the minimum interval is 3 months 2
• For adolescents and adults receiving varicella vaccine, the minimum interval is 4 weeks 2

Common Clinical Pitfalls to Avoid

• Do not delay catch-up vaccination waiting for the "ideal" age—start immediately with a minimum 4-week interval 1
• Do not restart the vaccine series if there's been a long gap—continue where you left off 1
• Do not use MMRV reflexively for first doses in young children due to increased febrile seizure risk 1
• Do not assume birth before 1957 guarantees immunity—during mumps outbreaks, consider MMR vaccination for exposed persons born before 1957 3

Safety Profile

Serious Adverse Events

• Serious outcomes (anaphylaxis, encephalitis/myelitis, Guillain-Barré syndrome, immune thrombocytopenia, meningitis, seizure) are rare, with incidence ≤6 per 100,000 doses in adolescents and adults 6

Common Non-Serious Events

• Arthropathy (263.0 per 100,000 doses), injection site reactions (157.0 per 100,000 doses), and rash (112.9 per 100,000 doses) are the most common non-serious outcomes 6
• Counsel vaccinees regarding anticipated local and systemic adverse events 6