HIV and AIDS can be devastating illnesses, but researchers have made progress over the years to help extend the lives of those affected. Now there is a new weapon in the fight against the spread of HIV as researchers show taking a pill before and after sex can help reduce the chance of infection drastically.
The study, published Tuesday in the New England Journal of Medicine, comes from a team led by Dr. Jean-Michel Molina of Hopital Saint-Louis in Paris and Dr. Jean-Francois Delfraissy of the ANRS Research Agency in France. The researchers looked at those most at risk for infection, men and transgender women who had unprotected, anal sex with two or more partners within six months. As part of the study, all participants were counseled on HIV and STD prevention and were provided with condoms and lubricant.
About half of the four hundred participants received a placebo while about half were provided with Truvada, an antiretroviral drug, and neither the participants nor the researchers knew which group received which type of pill, which is called a double-blind study. The participants had enough supply of the drug to take one daily if needed, with an average participation time of about nine and a half months, but were instructed to take pills based on their sexual patterns. They were told to take two pills before they had sex, followed by a third pill twenty-four hours later, and a fourth pill twenty-four hours after that. If the participants had frequent sex, they were instructed to take a daily pill plus two pills after sex. The technique of taking the pills as needed is called pre-exposure prophylaxis, or PrEP, and this method gives people an alternative choice to taking a pill every day.
The researchers found that participating in the study did not seem to affect the sexual behavior of the participants. However, it did seem to affect their chances of contracting HIV.
During the course of the study, some of the at-risk participants did contract HIV. In the placebo group, fourteen people acquired HIV. However, only two people in the group taking Truvada acquired HIV. This means that taking Truvada can reduce the chance of contracting HIV by about eighty-six percent.
It turns out that those two taking Truvada who did get HIV had not taken their pills at all. This seems to indicate that the pills are actually more effective than the study demonstrated, when taken properly. Adherence to medication instructions was actually a problem throughout the study, with 29 percent of participants taking pills less often than they should have and another 28 percent not taking any pills at all. However, with study participants taking a median of fifteen pills a month, the researchers found that most people were confident in their ability to take their medication as needed.
Two other recent trials of Truvada for HIV prevention involved heterosexual women, and did not seem to show a benefit. However, the researchers suspect that low adherence to medication instructions is the reason.
Truvada combines two antiviral medications in one. The drug helps block HIV infection by preventing the virus from reproducing when it enters one of the body’s cells. This means the virus is not able to reproduce and spread throughout the body, causing HIV infection which could lead to AIDS. The pill could cause some mild side effects such as nausea and abdominal pain.
While more studies are needed, the research so far seems to indicate that Truvada is promising for protecting at-risk people and limiting the spread of HIV through the population. The researchers are continuing to work with the study participants, seeing if adherence improves over time and if they can find ways to improve adherence to prevent HIV in even more people. With greater adherence, this medication could one day help to eradicate HIV from the population once and for all.