AIDS Vaccine Moves Forward
In the trial of the virus booster, 48 healthy volunteers got either fake shots or different doses of the vaccine. After three shots, nearly three in five of the high-dose subjects developed anti-HIV killer T cells.
This isn't as bad as it sounds. After all, the two parts of the vaccine are supposed to be used together. The main point of the study was to show that the vaccine is safe. These are about the same results seen in early monkey studies.
Human tests using both parts of the vaccine began in December 2001. Results should be ready in a year. These anxiously awaited findings will make or break the vaccine. If it looks good, Merck will go ahead with large-scale studies.
Emini warns that even if everything goes perfectly -- something that rarely happens in medical research -- it will be at least five years before the vaccine is ready for use.
One ominous warning came from a monkey study reported earlier this year in the journal Nature. One of the monkeys that at first seemed to be protected against AIDS later got sick and died. What happened? The sneaky AIDS virus found a way around the vaccine. It's not clear that this would happen in people -- but it's a reminder of how unrelenting and clever a killer HIV can be.
Meanwhile, two other AIDS vaccines are in much more advanced stages of testing. A protein-based vaccine from VaxGen is in advanced clinical trials in Thailand and the U.S.; results are expected soon. And the U.S. Department of Defense is about to begin large-scale trials of a poxvirus-based vaccine in Africa and Thailand.
Test-tube evidence makes many researchers doubtful about the VaxGen product, AIDSVax. But the truth is that nobody knows whether a vaccine will work until it's tested on a large scale.