JOIN USDemonstrating that taking a daily pill to prevent HIV infection can work in the real world, San Francisco’s largest private health insurer announced recently that not one of its 657 clients receiving the drug had become infected over a period of more than two years.
That outcome contradicted some critics’ predictions that so-called pre-exposure prophylaxis, or PrEP, would lead to less condom use and more HIV infections. A study published in Clinical Infectious Diseases found that the San Franciscans on PrEP, almost all of whom were gay men, did use fewer condoms — and contracted several other venereal diseases as a result. But none got HIV.
Most other sexual infections, while potentially dangerous, can be cured with antibiotics. HIV cannot, although it can be controlled with anti-retroviral drugs taken for life. “This is very reassuring data,” said Dr Jonathan Volk, an epidemiologist for the insurer, Kaiser Permanente of San Francisco, and the study’s lead author. “It tells us that PrEP works even in a high-risk population.”
Observational studies like this one are not considered as scientifically rigorous as randomised clinical trials in which some participants receive a placebo. But Jonathan and his colleagues followed a large number of men engaged in very risky behaviour from mid-2012, when the Food and Drug Administration approved the use of a two-drug combination called Truvada for prevention of HIV infection, through February of this year. That amounts to 388 “person years” of observation.