Incidence of Herpes Zoster Among Children: 2003-2014

BACKGROUND AND OBJECTIVES:After the 1996 introduction of routine varicella vaccination in the United States, most studies evaluating pediatric herpes zoster (HZ) incidence reported lower incidence over time, with varying degrees of decline. Using the combined databases of 6 integrated health care organizations, we examined HZ incidence in children over a 12-year period in the varicella vaccine era.METHODS:This study included children aged 0 through 17 years from 2003 through 2014. Using electronic medical records, we identified HZ cases through International Classification of Diseases, Ninth Revision diagnosis code 053. We calculated HZ incidence rates per 100000 person years of health plan membership for all children and among children who were vaccinated versus unvaccinated. We calculated rates for the 12-year period and examined temporal trends. Among children who were vaccinated, we compared HZ rates by month and year of age at vaccination.RESULTS:The study included 6372067 children with >= 1 month of health plan membership. For the 12-year period, the crude HZ incidence rate for all subjects was 74 per 100000 person years, and the rate among children who were vaccinated was 38 per 100000 person years, which was 78% lower than that among children who were unvaccinated (170 per 100000 person years; P < .0001). Overall HZ incidence declined by 72% (P < .0001) from 2003 through 2014. Annual rates in children who were vaccinated were consistently lower than in children who were unvaccinated.CONCLUSIONS:With this population-based study, we confirm the decline in pediatric HZ incidence and the significantly lower incidence among children who are vaccinated, reinforcing the benefit of routine varicella vaccination to prevent pediatric HZ.