Chickenpox Vaccination Schedule for Children
Children should receive their first chickenpox (varicella) vaccine at 12 to 15 months of age, followed by a second dose at 4 to 6 years of age. This two-dose schedule provides 98% protection against varicella disease and 100% efficacy against severe disease 1.
First Dose Timing
The initial varicella vaccine dose is administered between 12 to 15 months of age, though it can be given anytime from 12 months through 12 years of age 2, 3. This timing aligns with other routine childhood immunizations, and the vaccine can be given simultaneously with the MMR (measles-mumps-rubella) vaccine at the same visit 2.
Second Dose Timing
The second dose is routinely recommended at 4 to 6 years of age (before kindergarten or first grade entry), though it can be administered earlier if needed 1, 3. The minimum interval between doses is 3 months for children under 13 years 1.
Vaccine Options and Considerations
Two vaccine formulations are available:
- Monovalent varicella vaccine (Varivax): Approved for ages 12 months and older
- Combination MMRV vaccine (ProQuad): Approved only for children 12 months through 12 years 1, 3
Important Caveat for First Dose (12-47 months)
For the first dose in children aged 12 through 47 months, providers should use separate MMR and varicella vaccines rather than MMRV if there are barriers to clearly communicating risks 2. This is because MMRV carries a slightly increased risk of fever (22% vs 15%) and febrile seizures (approximately 1 additional febrile seizure per 2,300-2,600 doses) compared to separate injections 2.
Children with a personal or family history of seizures should receive separate MMR and varicella vaccines rather than MMRV for the first dose 2.
No Increased Risk for Second Dose
For children 48 months and older receiving their first dose, and for the second dose at any age, MMRV is generally preferred because there is no increased risk of febrile seizures in this age group, and it reduces the number of injections 2.
Rationale for Two-Dose Strategy
The two-dose schedule was implemented because single-dose vaccination showed only 80-85% effectiveness, leading to continued breakthrough cases and outbreaks in highly vaccinated school populations 1. Two doses provide:
- 98% protection against any varicella disease (vs 94% for one dose)
- 100% protection against severe disease
- 3.3-fold reduction in breakthrough varicella risk 1
Adolescents and Adults
For individuals 13 years and older without evidence of immunity, two doses should be given at a minimum interval of 4 weeks 1, 3.