Vaccination against varicella zoster virus (VZV) can markedly reduce the incidence of and morbidity from herpes zoster and postherpetic neuralgia among older adults, says a study in the New England Journal of Medicine.

A new vaccine could reduce the 1 million cases of herpes zoster that occur each year in the United States.

Researchers from the Shingles Prevention Study Group conducted a randomized, placebo-controlled, double-blind clinical trial at 22 sites. The Shingles Prevention Study is a cooperative study from the Department of Veterans Affairs in collaboration with the National Institute of Allergy and Infectious Diseases and with Merck, which holds the investigational new drug application on the vaccine used in this study.

The incidence and severity of herpes zoster are known to increase with advancing age, especially after age 60, and complications such as postherpetic neuralgia occur in almost half the cases of herpes zoster among older patients.

So, for this study, researchers recruited 38,546 adults ages 60 and older to receive either the investigational vaccine (Oka/Merck) or placebo treatment and followed them for three years.

Study results showed that the VZV vaccine:

 Reduced the incidence of herpes zoster by 51%. Of 957 confirmed cases, 642 occurred among patients who received placebo vs. 315 among patients who received the vaccine.

 Reduced the incidence of postherpetic neuralgia by 67%. Of 107 cases of postherpetic neuralgia, 80 occurred among placebo recipients vs. 27 among vaccine recipients.

Reduced the burden of illness by 61%. This measure considers the incidence, severity and duration of the associated pain and discomfort associated with herpes zoster.

The researchers believe the vaccine boosts immunity to the varicella zoster virus, although they say that further study is necessary to confirm this. Previous studies have shown that varicella zoster vaccines can significantly increase cell-mediated immunity to VZV in immunocompetent older adults.

An estimated 1 million or more cases of herpes zoster already occur each year in the United States, with substantial morbidity among older adults due to disabling pain and discomfort of herpes zoster and postherpetic neuralgia. Thus, a means of prevention would offer important medical and economic benefits, the researchers say.

Oxman MN, Levin MJ, Johnson GR, et al. A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults. N Engl J Med 2005 Jun 2;352(22):2271-84.

Vol. No: 142:7Issue: 7/15/2005