Waning immunity to varicella in infants of human immunodeficiency virus-seropositive and -seronegative mothers.

Immunity to varicella in HIV-exposed and -unexposed infants born to unvaccinated mothers, acquiring protective antibodies at birth declined to nonprotective (<1:8) levels by 5 months of age. Therefore, infants become susceptible to varicella before 12 months, which is the recommended time for varicella immunizations in the United States. Vaccination of susceptible HIV-seronegative women in the postpartum period may be important to consider.