Experimental Shingles Vaccine Proves Effective in Nationwide Study

In one of the largest adult vaccine clinical trials ever, researchers have found that an experimental vaccine against shingles (zoster vaccine) prevented about half of cases of shingles -- a painful nerve and skin infection -- and dramatically reduced its severity and complications in vaccinated persons who got the disease, according to the National Institute of Allergy and Infectious Diseases (NIAID).

The findings appear in the June 2 issue of The New England Journal of Medicine. The Shingles Prevention Study, conducted over five-and-a-half years, was led by the Department of Veterans Affairs (VA) and carried out in collaboration with the NIAID and Merck & Co.

The trial was conducted at 22 study sites nationwide, including 16 VA medical centers and six clinical research sites outside the VA system coordinated through NIAID. Between November 1998 and September 2001, the multicenter research team enrolled more than 38,500 men and women age 60 or older into the study. Half of the participants received a single injection of the zoster vaccine -- a live, weakened form of varicella-zoster virus, the virus responsible for chickenpox; the other half received a placebo vaccine. Neither the researchers nor the participants knew who received vaccine and who received placebo until after the study was over.

During an average of more than three years of follow-up, the vaccine reduced the incidence of shingles by 51 percent: 642 cases of shingles occurred among those in the placebo group compared with only 315 in the vaccinated group. Among all vaccine recipients, the total burden of pain and discomfort due to shingles was 61 percent lower than in placebo recipients. Moreover, the zoster vaccine reduced the incidence of postherpetic neuralgia by two-thirds compared with placebo. The vaccine was well-tolerated, with the rates of serious adverse events low and local reactions at the vaccination site generally mild.