What are the administration guidelines and precautions for the Measles, Mumps, and Rubella (MMR) vaccine in children and adults with various medical conditions?

MMR Vaccine Administration Guidelines

Standard Vaccination Schedule

All children should receive their first MMR dose at 12-15 months of age and their second dose at 4-6 years before school entry. 1, 2

First Dose Timing

• The minimum age for MMR vaccination is 12 months 2
• Routine administration occurs at 12-15 months as part of standard childhood immunization 1, 2
• For children who missed the routine schedule, the first dose can be administered up to 12 years of age 2

Second Dose Timing

• Routinely administered at 4-6 years (before school entry) 1, 2
• May be given earlier than 4-6 years, provided at least 4 weeks (28 days minimum interval) have elapsed since the first dose 2
• Children who have not received the second dose by school entry should complete the schedule by age 11-12 years 2

Minimum Interval Requirements

• The minimum interval between first and second MMR doses is 4 weeks 2, 3
• This 4-week minimum applies regardless of the child's age 2

MMRV Combination Vaccine Considerations

For children aged 12-47 months receiving their first dose, separate MMR and varicella vaccines are preferred over MMRV due to increased febrile seizure risk. 1, 2

First Dose (Ages 12-47 Months)

• MMRV carries approximately one additional febrile seizure per 2,300-2,600 doses compared to separate vaccines in children aged 12-23 months 1, 2
• Unless parents express a preference for MMRV after discussing risks and benefits, CDC recommends separate MMR and varicella vaccines 1, 2
• The 47-month cutoff was selected because approximately 97% of febrile seizures occur in children ≤47 months of age 1, 2

Second Dose or First Dose ≥48 Months

• MMRV vaccine is generally preferred over separate injections for the second dose at any age (15 months-12 years) or for the first dose at ≥48 months 1, 2
• Post-licensure studies demonstrated no increased febrile seizure risk in children aged 4-6 years receiving MMRV 2

Seizure History Precaution

• A personal or family history (sibling or parent) of seizures of any etiology is a precaution for MMRV vaccination 1, 2
• Children with personal or family seizure history should receive separate MMR and varicella vaccines instead of MMRV 1, 2

Catch-Up Vaccination

Previously unvaccinated children and adolescents should receive 2 doses of MMR vaccine with a minimum 4-week interval between doses, starting immediately regardless of current age. 1, 2

Key Principles

• There is no need to restart a vaccine series regardless of time elapsed between doses 2
• Administer 2 doses during any visit, with ≥4 weeks between doses 2
• Do not delay catch-up vaccination waiting for an "ideal" age—start immediately 2

Adult Vaccination

Adults at high risk for exposure require 2 doses of MMR vaccine; other adults aged ≥18 years need 1 dose. 3

High-Risk Adults Requiring 2 Doses

• Healthcare personnel 3
• Students attending colleges or post-high school educational institutions 3
• International travelers 3
• Minimum 4-week interval between doses for adults 3

Standard-Risk Adults

• One dose recommended for adults aged ≥18 years not at high risk 3

Vaccine Administration Details

MMR vaccine is administered as a 0.5 mL subcutaneous injection. 1

Available Products

• PRIORIX and M-M-R II are fully interchangeable 1
• Vaccination should not be deferred when the manufacturer of previously administered vaccine is unknown or unavailable 1
• PRIORIX is safe and immunogenic when administered as a second dose after M-M-R II 1

Timing with Other Vaccines

MMR can be administered concomitantly with other routine childhood vaccines at different anatomic sites. 1

Simultaneous Administration

• May be given simultaneously with other live and non-live vaccines without safety concerns or immune interference 1

Sequential Administration

• If not given simultaneously, MMR may be administered at any time before or after an inactivated vaccine 1
• Must be separated by ≥28 days (4 weeks) before or after another live, attenuated vaccine 1
• Exception: varicella vaccine requires a minimum 3-month interval if not given simultaneously 1

Contraindications and Precautions

MMR should not be administered to severely immunocompromised individuals or those with history of severe allergic reactions to vaccine components. 1, 2

Absolute Contraindications

• History of severe allergic reactions (anaphylaxis) to any vaccine component 1
• History of severe allergic reaction after a previous dose of any measles, mumps, or rubella virus-containing vaccine 1
• Severe immunosuppression 2

Special Populations

HIV-Infected Individuals

• Asymptomatic HIV-infected children without severe immunosuppression should receive MMR vaccine as soon as possible upon reaching 12 months of age 2, 3
• Consider administering the second dose as early as 28 days after the first dose in HIV-infected children 2
• MMR is contraindicated in severely immunocompromised HIV patients 2
• Children with perinatal HIV infection vaccinated before effective antiretroviral therapy (ART) should be revaccinated with 2 appropriately spaced doses once effective ART is established 3

Safety Profile

Serious adverse events after MMR are rare in all age groups, with incidence ≤6 per 100,000 doses. 4

Common Non-Serious Events

• Arthropathy: 263.0 per 100,000 doses 4
• Injection site reactions: 157.0 per 100,000 doses 4
• Rash: 112.9 per 100,000 doses 4
• Fever and allergic reactions occur but are generally well-tolerated 4

Serious Events (All Rare)

• Anaphylaxis, encephalitis/myelitis, Guillain-Barré syndrome, immune thrombocytopenia, meningitis, and seizures all have incidence ≤6 per 100,000 doses 4
• No significant elevation in serious outcomes during risk windows compared to control windows 4

Febrile Convulsion Rates

• Overall frequencies of febrile convulsions are ≤0.4% across all age groups 5
• Frequency occurring 7-10 days post-vaccination is approximately 5.7 per 10,000 doses 5

Adverse Event Reporting

All adverse events following MMR administration should be reported to the Vaccine Adverse Event Reporting System (VAERS). 1

• Reports can be submitted online, by fax, or by mail 1
• Additional information available at 1-800-822-7967 or https://vaers.hhs.gov 1