In 2012, the U.S. Food and Drug Administration approved the pill, known as Truvada, for so-called pre-exposure prophylaxis (PrEP) against HIV, the virus that causes AIDS. Uninfected individuals who take Truvada every day can cut their risk of getting HIV during sex by more than 90 percent, according to the U.S. Centers for Disease Control and Prevention (CDC).
Taking an anti-HIV pill shortly before sex and for a few days afterwards can help protect people against infection with the human immunodeficiency virus, according to researchers in France and Canada.
That phase of the trial ended in 2014, after which the researchers offered Truvada to all the participants.
After an average of about 18 months, the risk of HIV among the 362 participants fell 97 percent, compared to results with the dummy pill in the first phase of the study.
Dr. Jean-Michel Molina of Hopital Saint-Louis in Paris, one of the lead investigators, told Reuters Health he’s amazed at how effectively this strategy prevents HIV.
For the trial, people took two pills 24 hours before sex. They took one tablet 24 hours later, and another tablet 48 hours later. If they had continuous sexual activity, they were told to take a pill each day and a pill for the following two days after last having sex.
During the first part of the trial, there were 6.6 new infections per year among every 100 people taking the dummy pill, versus only 0.91 new infections per year among every 100 people using PrEP.
When everyone started using “on demand” PrEP, the rate of new infections fell even further, to 0.19 per 100 people per year.