I recall three years ago, at the International AIDS Conference in Toronto, hearing virologist Francoise Barre-Sinoussi of the Institut Pasteur in Paris question whether development of an AIDS vaccine would even be feasible. Now the unexpected has occurred. Researchers working in Thailand have reported modest results in preventing HIV, using two genetically engineered AIDS vaccines in combination.
"I don't want to use a word like 'breakthrough,' but I don't think there's any doubt that this is a very important result," Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, was quoted as saying in today's New York Times.
The NIH was one of the supporters of the trial, along with the U.S. Army, the Thai Ministry of Public Health, Sanofi-Pasteur and Global Solutions for Infectious Diseases. The trial involved 16,000 volunteers in Thailand who came from a cross-section of the adult population. Half were given six doses of the two vaccines in 2006, and the other half got placebos.
Over the course of three years, 74 on placebo became infected with HIV while only 51 of those who received the vaccine combo did. The researchers said those figures meant the vaccine was 31.2 percent effective.
There are many unanswered questions about the vaccine. For one, scientists don't understand how it works; individually the two vaccines failed previous trials. Moreover, the vaccine can't be used worldwide because it was only designed against the strains that are prevalent in Thailand.
Still, it's encouraging that after multiple failures, an approach has shown promise. At the very least, this serves as a proof of principle and could re-energize the search for this elusive potion.
