Background: 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.
Methods: 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.
Results: 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).
Conclusions: 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.