Varicella vaccine was licensed for use in the U.S. in 1995. The Centers for Disease Control and Prevention and AAP recommend children routinely receive doses at 12 to 15 months and 4 to 6 years. However, children who receive the vaccine as well as those who contract varicella may experience a re-emergence of the virus, causing herpes zoster.
Researchers set out to look at rates of herpes zoster in vaccinated vs. unvaccinated children using health records from nearly 6.4 million children from 2003-’14. During that time, herpes zoster infections fell 72%, according to “Incidence of Herpes Zoster Among Children: 2003-2014,” (Weinmann S, et al. Pediatrics. June 10, 2019, https://doi.org/10.1542/peds.2018-2917).
Results showed vaccinated children experienced herpes zoster at a rate of 38 per 100,000 person-years compared to 170 per 100,000 for unvaccinated children, a 78% difference.
After dividing the children into age groups, researchers found the trend of lower herpes zoster rates among vaccinated children held true for all but the youngest children. Children age 1 year had a 140% higher herpes zoster risk when they were vaccinated.
Infection rates were higher in girls than boys and immunosuppressed children compared to non-immunosuppressed children. They also were higher for those who received one dose of varicella vaccine compared to those who received two.
“That the varicella vaccine prevents not only varicella but zoster as well is an exciting dual benefit from the varicella vaccine, further improving the health of children by immunization, Anne Gershon, M.D., wrote in a related commentary.
She called for additional study into how the vaccine protects against both diseases and for how long.