A recent clinical human trial of an AIDS vaccine made by Merck failed to prevent HIV, and instead might have increased the risk of getting AIDS by vaccine recipients. The study found that among 914 male volunteers who received the drug, 49 got HIV, while among 922 male volunteers with a placebo, 33 got HIV. While about two dozen groups are pursuing an AIDS vaccine, the one in the recent trial was the only one being tested and produced by Merck, and only one of two that has going into major clinical trials.
There are two main ways to produce a viable vaccine for HIV/AIDS. The first method, which is more straightforward but also more difficult, is to get the body to produce antibodies that react to HIV. Another potential AIDS vaccine produced by the National Institute of Health follows that path. The second method requires getting a cellular reaction to occur after HIV attempts to infect cells. This cellular reaction would case infected cells to defeat HIV after an initial infection. The majority of vaccines in development follow the second method because of problems getting the body to produce effective antibodies to HIV.
The research for an HIV vaccine is intended to stop the growth of AIDS, which currently infects about 40 million people. Prevention measures such as condoms, circumcision, and education have not been able to slow down the rate of the disease, which is growing at 4.3 million new infections per year. Experts in the field believe that despite setbacks, the search for a vaccine is likely to succeed, but warn that such a search would be “a marathon, not a sprint.”