Herpes Zoster in a Partially Vaccinated Pediatric Population in Central Israel

Abstract

This study was performed during an era of partial vaccination with varicella vaccine in Israel to characterize ambulatory pediatric herpes zoster (HZ) cases in a population with partial varicella vaccination coverage. Data were collected from computerized databases of a population of 114,000 children. Records of children aged 0-18 years, diagnosed with HZ during 2006 to 2008 were reviewed by pediatric infectious diseases experts. Telephone interviews were done with a sample of the parents to get further clinical details. Of 692 medical records reviewed, 450 cases were approved for analysis, and 77 interviews were conducted. Incidence of HZ was 130 of 100,000 person life-years. Peak incidence was detected in children aged 9-11 years (222/100,000 person life-years). Pain and fever accompanied 52% and 13% of episodes, respectively. Higher risk for HZ was found in children who had varicella during their first year of life (relative risk and 95% confidence interval: 13.5[9.6-18.8]; P < 0.001), and in children who had varicella during the second year of life (relative risk = 2 [1.5-2.6]; P < 0.001). Vaccination was found to be protective against HZ (relative risk = 0.42 [0.33-0.55]; P < 0.001). The epidemiology of HZ seems to be changing in a population with partial varicella vaccination rate. Our results may suggest that children who contracted chicken pox in their first year of life may benefit from varicella vaccination.