Varicella-zoster vaccine

Excerpt

A live attenuated varicella vaccine, the Oka strain, was developed by Takahashi and his colleagues in Japan the early 1970s (Takahashi et al., 1974). This vaccine is now being adminstered to varicella-susceptible healthy children and adults in many countries; it is produced by at least 3 manufacturers worldwide (Merck and Co., Glaxo SmithKline, and Biken Institute/Aventis Pasteur). Although the vaccine was developed in Japan, the largest experience with it comes from the United States, where the Merck formulation was licensed for routine use in healthy susceptible individuals over the age of 1 year in 1995 (Centers for Disease Control, 1996). In both pre- and postlicensure studies (Gershon et al., , ; White, ; Sharrar et al., 2000) the vaccine was demonstrated to be extremely safe. Adverse effects in healthy persons are few and quite transient: a sore arm after the injection in 20%–25%, and a very minor rash resembling mild varicella in about 5%, usually appearing a month after immunization (White, 1997). A small proportion of vaccinees (15%) may also experience mild fever. It takes about a week to demonstrate antibodies to varicella-zoster virus (VZV) after immunization, but protection often results even after an exposure has occurred. As a result of widespread immunization of children, the epidemiology of varicella has begun to change in the United States, with a reported marked decline in incidence in sentinel areas, where active surveillance for the disease is being carried out (Seward et al., 2002). Vaccination is now being explored for the possibility of its preventing or modifying zoster. In a very real sense, the development of live varicella vaccine paved the way for the development of other vaccines against herpesviruses.