A vaginal gel can protect users against the human immunodeficiency virus (HIV), although it has to be used three hours after having sex. At the moment its efficacy and safety has only been tested in monkeys, but in the light of these findings, the researchers believe that it could be used in humans.

Developing new methods for preventing infection of the virus of AIDS in countries with few resources is a priority to reduce the spread of the epidemic. Until now, microbicidal gels had proved most effective, although they should be applied before intercourse, which compromised their employment in many women since having to be applied before it would imply knowledge and acceptance of the sexual partner. Now, the new gel, developed by a team from the Centers Disease for Control (CDC), Emory University and Merck Research Laboratories say this avoids the problem.

The gel was developed by a team coordinated by Charles Dobard and it works by blocking the integration of the virus. It is known that block integration prevents the virus from establishing an infection and prevents its ability to duplicate. In addition, as the integration of HIV into the cellular DNA takes about six hours, the gel has a wide window for treatment with inhibitors of the integrase until three hours after intercourse.

Now published in Science Translational of Medicine, the researchers found that the gel when applied 30 minutes prior to sexual intercourse could prevent HIV infection. But the most important thing was that the gel was equally effective when applied up to three hours after intercourse. The next step is to test gel in clinical trials and develop products inhibitors of viral integrase for women.