The Association between Varicella Vaccination and Herpes Zoster in Children: A Semi-National Retrospective Study.

Abstract

Varicella vaccination in children has been performed worldwide in recent years. Despite established effectiveness, many countries still do not routinely vaccinate children against varicella, probably due to concerns about complications, such as herpes zoster infection. We aimed to compare the herpes zoster incidence in children before and after implementing the mandatory varicella vaccine in Israel in 2008. As a secondary aim, we characterized several parameters, including age, sex, and ethnic sector among herpes zoster cases, and we evaluated the complication rate to identify data relevant to the immunization status of the pediatric population. A retrospective study was conducted between 2000 and 2021, including patients aged 0-18 years old in a large cohort in southern Israel. A time series analysis and complication rates evaluations were performed in the pre- and post-vaccination eras. A total of 109.24 herpes zoster cases per 100,000 population per year were diagnosed between 2000 and 2007 (pre-vaccination era), compared to 354.71 herpes zoster cases per 100,000 population per year diagnosed between 2008 and 2021 (post-vaccination era) (p < 0.001). No change in the complication rate was documented. Thus, we concluded that there is an association between the varicella vaccine implementation program and the increase in the rate of herpes-zoster occurrence without a concurrent negative contribution to herpes zoster-related morbidity.