AIDS Vaccine Shows Promise for First Time in Thai Study

(Bloomberg) — An experimental vaccine prevented HIV infections for the first time, a breakthrough that has eluded scientists for a quarter century.

A U.S.-funded study involving more than 16,000 volunteers in Thailand found that a combination of ALVAC, made by Paris- based Sanofi-Aventis SA, and AIDSVAX, from VaxGen Inc., of South San Francisco, cut infections by 31.2 percent in the people who received it compared with those on a placebo, scientists said today in Bangkok. Neither vaccine had stopped the virus that causes AIDS when tested separately in previous studies.

The finding represents a revival in a campaign that appeared to stall just two years ago when use of Merck & Co.’s experimental Ad5 vaccine boosted some people’s chances of infection in a study. The latest result will transform future research, said Mitchell Warren, director of the New York-based AIDS Vaccine Advocacy Coalition.

“Wow,” said Warren, who was not involved in the study, in a telephone interview today. “We are in a new place in the search for an AIDS vaccine. It’s safe to say that the scientific community is caught off-guard.”

The findings don’t mean the vaccine can be delivered worldwide, because of the complexity of the process and the fact that it’s based on old technology, Warren said. Instead they will serve to spur scientists to look for better combinations in more user-friendly regimens with higher success rates, he said.