An antiretroviral microbicide gel can cut HIV infection in women by more than 50 % if used consistently.

Quarraisha Abdool Karim, Centre for the AIDS Program of Research in South Africa (CAPRISA), Durban, and her colleagues tested a 1 % vaginal gel formulation of the antiretroviral drug tenofovir, manufactured by Gilead Sciences, Foster City, California. The study involved 889 women in South Africa aged between 18 and 40 years who were HIV-negative, sexually active and at high risk of HIV infection.

Unexpectedly, the gel was also shown to reduce Herpes simplex virus 2 (HSV-2) infections by 51 %. The formulation is the first to successfully prevent HSV-2, which is important, because the risk of becoming infected with HIV doubles for women with HSV-2.

More tests have to be performed, a tenofovir gel product will not be available for at least a year or two.

• Nature 2010,
  DOI: 10.1038/news.2010.363