An experimental new gel might protect women from the AIDS virus even after they have sex, researchers reported Wednesday.
Tests in monkeys show the gel, which contains an HIV drug that stops the virus from infecting cells, can work even after the virus is in the body. If the same holds true in humans, it would offer a way for women to protect themselves from infection after intercourse.
The human immunodeficiency virus that causes AIDS can be transmitted in blood, semen and breast milk. Most people are infected sexually and in Africa, where most cases are, 60 percent of HIV patients are women. Almost all were infected by husbands or other sexual partners.
Experts agree women need a way to protect themselves from the virus, especially for victims of rape and in societies where they cannot demand that their husbands or other men wear a condom.
Studies have shown that so-called microbicide gels or creams can work — in 2010, researchers reported on one that reduced a woman’s risk of infection by 50 percent after one year of use and 39 percent after 2 1/2 years. It contained a different HIV drug, called tenofovir.
But last year, researchers reported some bad news: women were not able to use either drugs or a gel consistently enough to protect themselves.
Dr. Walid Heinene of the Centers for Disease Control and Prevention tested a gel containing the HIV drug raltegravir. It protected monkeys when given before they were infected with HIV vaginally — something that simulates natural sexual transmission of the virus. But it also prevented infection when applied as long as three hours after sex, they report in the journal Science Translational Medicine.
The AIDS virus infects cells in a complex series of steps — it first finds a cell, attaches to it, gets through its protective wall, finds its way into the nucleus and then turns the cell into a virus factory. The new drug acts against a later step in the process, which may buy time for women, Heinene’s team said.