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Women will take HIV-prevention pills under the right circumstances, CDC study shows

Knowing they’re receiving medicine, and not a placebo, makes women more likely to take it

Jeffrey Beall / Wikimedia Commons

Women in developing countries will take HIV-prevention drugs — as long as they know they're receiving them, and not a placebo, a new study suggests.

Previous research — in placebo-controlled trials — showed that the treatment didn’t work, mainly because participants didn’t take their pills. A recent study of 5,000 women in Zimbabwe, for instance, showed that less than 40 percent of the blood samples taken in the study contained detectable levels of the drug. As a result, some scientists speculated that false rumors about the drug's safety and lack of social support — combined with the possibility that the women had been assigned a placebo — may have discouraged the women from taking the drug. Many scientists hoped that this trend would change if women were guaranteed that the drug was the real thing.

Now, it appears that these suggestions may have been correct. Today's CDC-led study showed high levels of the drug in the participants' blood, including in the women.

A total of 229 heterosexual individuals in Botswana were enrolled in the trial, a little over half of whom were men. The participants in the trial already knew a lot about the drug, because they had all participated in a previous, placebo-controlled trial. The researchers followed the participants for a period of 12 months, and at the end of the trial no one had contracted HIV. The participants who stayed in the trial and had their blood sampled — 120 total — had a high level of oral PrEP in their blood, and 58 percent said they took the drug regularly.

"These results are very exciting and encouraging as to the real life use of PrEP in women," says Erika Aaron, an adult nurse practitioner at Drexel University who didn't work on this trial. "It may be that there is an increased awareness of the risk factors for women and the use of PrEP in these communities." It follows that this information would lead to improved adherence, she says.

The population studied was "highly selected."

The population studied raises some questions about how reproducible these results might be. For one, the study was small; the researchers only collected blood from 120 participants. For another, all of the participants were familiar with the drug, having already gone through a previous trial. "This is a highly selected group of people that were retained in the life of the original study and that clearly must have indicated that they wanted to stay on the drug and planned to be adherent and less mobile," says Stefan Baral, a physician epidemiologist at Johns Hopkins University.

So what the study may really be saying is that women who are well-informed about the drug, and who think they’ll benefit from it, are more likely to take it routinely. That may actually be good news, since a woman who requests PrEP from her doctor may share those characteristics.

Unfortunately, the "exorbitant costs" associated with PrEP will prevent many women from accessing the drug, Arron says. If the drug — which is effective — costs less, that might make the HIV prevention strategy more prevalent in the developing world.

Correction: An earlier version of this article stated that "a total of 299 heterosexual individuals in Botswana were enrolled in the trial." That number was wrong. The study enrolled 229 participants. The article also stated that 59 percent of participants took the drug regularly. That number is actually 58 percent. We regret these errors.