More than a quarter-century after scientists discovered the virus that causes AIDS, researchers have finally shown that an experimental vaccine can block at least some infections, marking the first small but significant step toward eventual control of this lethal pandemic.
The benefits of the vaccine were modest, only a 31 percent reduction in the number of new infections. But coming on the heels of previous vaccine studies that either showed no benefit at all or actually increased the risk of contracting the disease, the study buoys the hopes of researchers who had nearly given up on ever finding an effective way to block the spread of the virus.
The results were released in Bangkok, where the research was conducted by a team including Thai researchers, the U.S. Army and the U.S. National Institutes of Health.
“This is a historic day in the 26-year quest to develop an AIDS vaccine,” Dr. Alan Bernstein, executive director of the Global HIV Vaccine Enterprise, who was not involved in the research, said in a statement.
“We now have evidence that it is possible to reduce the risk of HIV infection with a vaccine,” said Mitchell Warren, executive director of the AIDS Vaccine Advocacy Coalition, in his own statement.
The trial, which began in 2003, had been disparaged by some as a waste of time and money because each of the two vaccines used had been shown in individual trials to produce no benefit. But researchers speculated that using them together, with one vaccine priming the immune system and the second boosting that response, would be more effective, and their optimism about the combination has been validated.
