AIDS Therapies and Vaccines

The search for a vaccine that would protect people from HIV infection, by blocking the entry of the virus into the immune cells, has been ongoing almost as long as the search for AIDS treatment strategies. At least 25 experimental vaccines have been created since identification of the disease. Unfortunately, few have proved even promising enough to complete the large-scale testing on human volunteers that is required to demonstrate the vaccine's success.

Some initial vaccine trials, however, have occurred. In June 1998, a large-scale test began with 5,000 volunteers in 30 cities in the United States, and a smaller group in Thailand. Volunteers were given a series of injections that hopefully stimulate the immune system to resist the two most common strains of the AIDS virus. Previous trials using smaller numbers of people documented that 99.5% of the vaccinated volunteers produced strong levels of resistance in their immune cells, which then target and kill infections such as HIV. The trial was expected to last three years. The conclusions of the trial are expected by 2004.

Also in 1998, a group of researchers at the University of Michigan proposed to develop a vaccine that would prevent someone with HIV from passing it on to someone else. Such a vaccine would be given within the first three months after infection, when the virus is most contagious. Their theories resemble those used to create the Salk polio vaccine in the 1950s, which reduced the polio virus symptoms and drastically reduced its ability to infect others, virtually eliminating the disease within a decade. The feasibility of this approach remains to be experimentally examined.