A fresh look at varicella vaccination.

The varicella vaccine is a live attenuated varicella zoster virus (VZV), first produced by Michiaki Takahashi (1974). Subsequent development of the fluorescent antibody to VZV membrane antigen test (FAMA), an immune correlate, permitted vaccine efficacy to be established, initially in immunodeficient and then in typical children and adults. Varicella vaccine is effective and safe; universal vaccination has almost eliminated varicella; moreover, endogenous boosting from subclinical VZV reactivation has evidently prevented an anticipated epidemic of zoster from occurring in response to the vaccine-induced loss of circulating varicella. The vaccine virus, moreover, reactivates less frequently than wild-type and an adjuvanted subunit vaccine against VZV gE safely prevents zoster. Doing so is important because VZV establishes latency and reactivates in sympathetic and enteric neurons; therefore, in addition to the painful cutaneous rash and postherpetic neuralgia of zoster, VZV reactivation can be an occult cause of vasculopathy, stroke, intestinal dysmotility, and achalasia.