Incidence of herpes zoster among children and adolescents in a community with moderate varicella vaccination coverage.

Active surveillance for herpes zoster (HZ) was conducted for 2 years (2000-2001) in the Antelope Valley community of 312,000 residents among 290 public and private schools, daycares, and healthcare providers. The true ascertainment-adjusted HZ incidence rate is 307 per 100,000 person-years and 138 per 100,000 person-years among children <10 and individuals aged 10-19, respectively. The unadjusted rate among vaccinated children is 9.5 per 100,000 person-years and an estimated 22 per 100,000 vaccine doses. Unvaccinated children with a previous history of varicella may have greater sensitivity to exogenous exposures (boosting) and a poorer cell-mediated response following primary infection relative to older age groups.