Varicella Vaccination After Neonatal Infection
Direct Answer
A child who contracted varicella at 21 days of age has acquired natural immunity and does not require varicella vaccination. Natural varicella infection, regardless of age at infection, provides lifelong immunity and eliminates the need for subsequent vaccination.
Rationale for No Vaccination
Natural infection confers lifelong immunity: Once a child has fully recovered from varicella, no varicella vaccination is needed, as natural infection provides permanent immunity 1
Age at infection does not affect immunity: Even though this infection occurred at 21 days of age (before the typical vaccination age of 12-15 months), the immune response to wild-type VZV infection is sufficient to establish lasting protection 2, 3
Natural immunity is considered evidence of immunity: Having documented varicella disease serves as evidence of immunity, which is one of the accepted criteria for determining protection against varicella 2, 3
Clinical Considerations
Documentation Requirements
Ensure proper documentation of the varicella infection in the child's medical record, as this will be needed for school entry requirements 3
Most schools accept documented history of varicella disease as evidence of immunity in lieu of vaccination records 3
Monitoring for Complications
While the child does not need vaccination, be aware that infants under 1 year have 6 times higher hospitalization rates than older children due to increased complication risks 1
Watch for late complications such as bacterial superinfection, particularly invasive group A streptococcal infections, which are the most common serious complications requiring hospitalization 1
Future Considerations
Herpes zoster risk: This child will carry lifelong risk of herpes zoster (shingles) from reactivation of the latent VZV established during this neonatal infection 4, 5, 6
The child may be a candidate for zoster vaccination later in life (typically age ≥50 years) 4
Common Pitfall to Avoid
Do not confuse this scenario with maternal varicella exposure during pregnancy or perinatal varicella: A neonate who contracts varicella at 21 days of age has acquired the infection postnatally and will mount a normal immune response, unlike neonates infected perinatally (5 days before to 2 days after delivery) who may have severe disease due to lack of maternal antibodies. This 21-day-old infant's infection occurred well outside the high-risk perinatal window.