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That HIV Vaccine We Were All Excited About? Maybe It’s Not Such a Big Deal After All


Scientists know it as ALVAC-AIDSVAX. You know it as the HIV vaccine that a Thailand study found could help reduce the risk of contracting the virus by a third — the one that everyone was sooooo thrilled about yesterday. But maybe it’s not such a big deal after all?

“The results were barely significant on statistical grounds,” relays the Washington Post. Wait. How could that be? If they were so insignificant, why was the HIV/AIDS community popping the bubbly?

In the study, volunteers in two provinces in central Thailand were randomly assigned to get vaccine or placebo shots. About 40 percent were women, and many were employed in manufacturing and shipping enterprises along Thailand’s coast. They were counseled on ways to avoid HIV infection and advised to use condoms.

There were few intravenous drug users and male homosexuals — groups at unusually high risk for HIV that make up most of the infected population in North America and Europe. In Africa and much of Asia, heterosexual intercourse is the most common route of infection.

Of 8,197 people who got vaccine, 51 became infected in the three years after their shots. Of the 8,198 who got placebo injections, 74 became infected. While that difference — 23 infections out of more than 16,000 people studied — is significant, it could have occurred by chance.

The results have at least one part of the AIDS research community doubting the vaccine as as significant development (though they don’t want their names in such a report, which makes sense).

On the other hand, even a modestly successful means of prevention is reason to celebrate, because it shows a vaccine is possible. In theory.

And then there’s this possibility: The (immediate) future of fighting HIV/AIDS lies not in a vaccine, but in PrEp drugs.