What is the recommended schedule for administering the combined measles‑mumps‑rubella‑varicella vaccine (ProQuad)?

MMRV ProQuad Vaccination Schedule

ProQuad should be administered as a two-dose series: the first dose at 12-15 months of age and the second dose at 4-6 years of age. 1, 2

Standard Dosing Schedule

• First dose: Administer at 12-15 months of age (may be given anytime from 12 months through 12 years) 1, 2
• Second dose: Administer at 4-6 years of age 1, 2
• Dose volume: Approximately 0.5 mL per dose, administered either intramuscularly or subcutaneously 2

Critical Timing Intervals

When transitioning from separate vaccines to ProQuad, specific intervals must be observed:

• At least 1 month must elapse between a dose of any measles-containing vaccine and ProQuad 2
• At least 3 months must elapse between a dose of any varicella-containing vaccine and ProQuad 2
• If administering ProQuad with other live vaccines (except varicella), allow at least 28 days between doses 1

Age-Specific Recommendations for First Dose

Ages 12-47 Months: Exercise Caution

For children 12-47 months receiving their first dose, CDC recommends using separate MMR and varicella vaccines rather than MMRV unless parents specifically prefer MMRV after counseling. 1

This recommendation is based on postlicensure safety data showing:

• One additional febrile seizure occurs per 2,300-2,600 children aged 12-23 months who receive the first dose of MMRV compared to separate MMR and varicella vaccines 1
• The increased risk occurs specifically during days 5-12 after the first dose 1
• Providers must discuss both benefits (one fewer injection) and risks (increased febrile seizure risk) with parents before administering MMRV as the first dose in this age group 1

Ages ≥48 Months: MMRV Preferred

For children ≥48 months receiving their first dose, MMRV is generally preferred over separate injections. 1

• No increased febrile seizure risk has been identified in this older age group 1

Second Dose Recommendations

MMRV is generally preferred over separate MMR and varicella vaccines for the second dose at any age (15 months-12 years). 1

• No increased risk of febrile seizures has been demonstrated for the second dose in children aged 4-6 years 1
• Using combination vaccine reduces injection burden and improves compliance 3

Important Precautions

Personal or Family History of Seizures

Children with a personal or family history (sibling or parent) of seizures of any etiology should generally receive separate MMR and varicella vaccines rather than MMRV. 1

• This precaution applies regardless of age 1
• The recommendation aims to avoid the small but measurable increased febrile seizure risk 1

Concomitant Administration

ProQuad may be administered simultaneously with other recommended childhood vaccines at separate injection sites: 1

• Haemophilus influenzae type b conjugate vaccine 4
• Hepatitis B vaccine 4
• Pneumococcal 7-valent conjugate vaccine 1
• Hepatitis A vaccine 1
• Hexavalent vaccines (DTaP-IPV-Hib-HepB) 4

Reconstitution and Storage

• Administer immediately after reconstitution 2
• If not used immediately, reconstituted vaccine may be stored at room temperature, protected from light, for up to 30 minutes only 2
• Discard if not used within 30 minutes 2

Common Pitfalls to Avoid

• Do not use MMRV routinely for first dose in children 12-47 months without explicit parental preference after counseling about febrile seizure risk 1
• Do not administer to pregnant females; pregnancy should be avoided for 3 months following vaccination 2
• Avoid salicylates for 6 weeks after ProQuad administration due to association with Reye syndrome following varicella infection 2
• Do not give immune globulins or blood products concurrently, as they may interfere with immune response 2