The impact of varicella vaccination on paediatric herpes zoster epidemiology: a Canadian population-based retrospective cohort study

The impact of universal varicella vaccination on herpes zoster (HZ) risk in unvaccinated and vaccinated children, and its long-term influence on HZ epidemiology, remains unknown. This retrospective cohort study used population-based administrative health data for children born between 1993 and 2018. A universal varicella vaccination programme implementation corresponded to decreased paediatric HZ incidence across age groups, in both vaccinated and unvaccinated individuals. Results from this study can hopefully be used to help inform varicella vaccination programme decision-making in other countries.