In its first large test, an AIDS vaccine has failed to shield an at-risk population from acquiring HIV, the virus that causes the disease.
The results, released by the biotechnology company VaxGen of Brisbane, Calif., may mark a turning point in AIDS-vaccine research, says Norman Letvin of Harvard Medical School in Boston. While VaxGen should be applauded for "a landmark effort" to get a vaccine to trial, he says, many scientists expected this vaccine to fail.
"This was a first-generation approach based on work done at a time when we had a very rudimentary understanding of the virus," says Letvin. The VaxGen vaccine, known as AIDSVAX, seeks to stimulate the generation of antibodies that attack HIV.
Newer, DNA-based approaches to an AIDS vaccine might work better because they deliver genes that encode proteins that could spur production of anti-HIV immune cells, Letvin says. Some such vaccines are entering early-stage human trials.