When preventing HIV, bacteria in the vagina matter
Some microbes appear to break down drug in prophylactic gel, making it less effective
Bacteria in the vagina affect whether a drug stops an HIV infection or is itself stopped cold.
A vaginal gel containing tenofovir, an antiretroviral drug used to treat HIV infection, was three times as effective at preventing HIV in women who had healthy vaginal bacterial communities as it was in women with a less beneficial mix. The finding may help explain why the effectiveness of these gels has varied in trials, researchers report in the June 2 Science.