The Centers for Disease Control and Prevention created a new vaginal gel that could protect women from contracting HIV, even if applied hours after sex.

Published in the journal, Science Translational Medicine, the researchers created a microbicide gel, a gel that kills or neutralizes viruses and bacteria that contains antiretroviral drugs that block processes after HIV infection, called integrase inhibitors. This means that the gel can be applied hours after sexual intercourse.

The gel contains a 1% solution of an antiretroviral drug called raltegravir, which decreases the amount of HIV in the blood.

“What we did in this work was we identified an anti-HIV drug that blocks virus integration in the DNA,” study co-author Walid Heneine told AFP. 

The researchers reported that about six hours after initial infection, the DNA of the virus moves into the DNA of animal cells. Raltegravir blocks this process.

To test the effectiveness of the gel against HIV infection, the research team first applied it to three female macaque monkeys 30 minutes before contact to HIV, while a group of 10 monkeys received a placebo gel. The gels were applied twice a week for a total of seven weeks.

Two out of three remained HIV-free who received the antiretroviral gel, compared with only one of the 10 monkeys that were given the placebo gel. 

The gel was then tested vaginally in six macaque monkeys, and was applied up to three hours after they were exposed to simian immunodeficiency virus (SIV), which is found in primates and is similar to HIV in humans, while four monkeys were given a placebo gel. The gels were applied twice a week for 2.5 months.

The study showed the gel prevented the virus in five of six monkeys, for an 84 percent success rate.

The researchers say, “We provide a proof of concept that topically applied integrase inhibitors protect against vaginal SHIV (simian/human immunodeficiency virus) infection when administered shortly before or 3 hours after virus exposure.”

Until now, only microbicide gels have been designed for application before sexual contact.

Additional Resources:

Postexposure Protection of Macaques from Vaginal SHIV Infection by Topical Integrase Inhibitors