TB Vaccine Provides Long-Lasting Protection

single dose of the BCG vaccine, which is used to prevent tuberculosis, provides protection against the disease for 50 to 60 years, a U.S. study shows.

single dose of the BCG vaccine, which is used to prevent tuberculosis, provides protection against the disease for 50 to 60 years, a U.S. study shows. BCG vaccination is no longer routine in the U.S., but it is still used to inoculate some at-risk populations and in some areas of the world where TB infection is common. Despite being in use for more than 80 years, the long-term effectiveness of the BCG vaccine has not been known, lead author Dr. Naomi E. Aronson, from the Uniformed Services University of the Health Sciences in Bethesda, Maryland, and colleagues note in the Journal of the American Medical Association. The new findings are based on a study of American Indians and Alaska Natives who were given the BCG vaccine or inactive “placebo” in the late 1930s and followed through 1998. A total of 1483 subjects received the vaccine and 1309 were given placebo. Although the rate of tuberculosis in both groups was very low, about half as many cases occurred in the vaccine group as in the placebo group, the authors report. Treatment with the vaccine reduced the risk of tuberculosis by 52 percent. A slight drop in vaccine effectiveness was noted over time, which was more apparent in men than in women, the researchers point out. This trial is the only study, “to our knowledge, to demonstrate that (the BCG vaccine) conferred a considerable degree of protection throughout most of the 60-year follow-up period,” the authors state. “These results should provide encouragement to investigators aspiring to produce a vaccine with similar or improved characteristics,” they add. (Source: Reuters Health, Journal of the American Medical Association, May, 2004)