An important safety issue related to the varicella vaccine is the impact on the epidemiology of herpes zoster both in vaccinees as well as in individuals previously infected with wild-type varicella.

Antiviral therapy is reserved for cases of varicella-zoster and herpes simplex infection.

Shingles, also called herpes zoster, is a painful skin rash caused by the varicella zoster virus (VZV), which is the same virus that causes chickenpox.