Impact of the varicella vaccine

The varicella vaccine may have been helpful in reducing the incidence of herpes zoster. A recent study published in Pediatrics confirms what other studies had previously reported.

The researchers used children aged 0 to 17 years from 2003 to 2014. They identified cases of herpes zoster using electronic medical records and looking for International Classification of Diseases, Ninth Revision diagnosis code 053. Researchers calculated the incidence rate of herpes zoster per 100,000 person years of health plan membership for all children and also among children who had been vaccinated versus those who had not been. Among children who had been vaccinated, they compared herpes zoster rates by month and year of age at vaccination.

The study included 6,372,067 children with ≥1 month of health plan membership. Over the 12-year period, the herpes zoster incidence rate for all children was 74 per 100,00 person years. The rate among children who had been vaccine for varicella was 38 per 100,000 person years, which was 78% lower than among children who were not vaccinated, 170 per 100,00 person years. The incidence of herpes zoster declined by 72% during the study period and the annual rates were consistently lower in children who had been vaccinated than in children who had not been vaccinated.

The researchers concluded that their results served as confirmation of the decline in herpes zoster incidence. The significantly lower incidence among children vaccinated for varicella highlighted the importance of routine varicella vaccination.