Fifteen years of routine childhood varicella vaccination in the United States—strong decrease in the burden of varicella disease and no negative effects on the population level thus far

Varicella (chickenpox), the primary manifestation of varicella-zoster virus (VZV) infection, is a usually mild disease in young children (1). Nevertheless, significant complications, e.g., bacterial super-infections of cutaneous lesions or neurological manifestations, occur in all age groups, with a higher incidence among older children, adolescents and adults (1-3). Without vaccination, VZV infection in temperate climates affects about 90% of children up to 10 years of age (4). After primary infection, VZV can remain latent in the neuronal ganglia and, after reactivation, may result in herpes zoster (shingles), with the highest burden of disease in the older population (1).