Despite the clinical gains a new generation of AIDS medications have yielded, drug-resistant strains of HIV and the frequency of their transmission increasingly threaten public health efforts to thwart the spread of AIDS, according to an analysis co-authored by the director of the Yale AIDS Program.

“Prevention of both development of HIV drug resistance as well as transmission of drug-resistant variants is a central issue of public health importance,” wrote Gerald H. Friedland, M.D., professor of medicine and epidemiology and director of the Yale AIDS Program, and Mark A.Wainberg, Ph.D., of the McGill University AIDS Center in Montreal. In their report, published in the June 24 issue of The Journal of the American Medical Association, the two sounded a warning about antiretroviral therapy.

Researchers have identified viruses resistant to the antiviral agents longest in use, according to the report. Current methods for detecting HIV resistance may be inadequate and resistance may be more widespread than previously thought. They also found that failure to adhere to just one of three medications in a regimen can lead to a resistance to all three.

The authors call for increased emphasis on adherence to medications and population-based studies of the prevalence, mechanisms and transmission rates of drug-resistant strains of HIV. “In the meantime,” they wrote, “prevention of both occurrence and transmission of drug-resistant HIV is important in the public health arena. These subjects must be addressed if antiviral therapy is to play its optimal role in blunting and altering the course of the HIV pandemic.”