Two new studies have added to the mounting evidence that HIV transmission can be virtually prevented if HIV-negative individuals take PrEP (pre-exposure prophylaxis) — also known as “Truvada” — a daily pill with similar medication as is used to actually treat HIV.
Both were unveiled this week at the Conference on Retroviruses and Opportunistic Infections in Seattle. The first, known as the UK PROUD study, originally began as a comparison between a group of gay men taking PrEP and a group that was going to wait a year before begin taking PrEP. So many in the latter group were becoming HIV positive that everybody in the group was immediately offered PrEP.
Ultimately, PrEP reduced the risk of HIV by 86 percent. Only 3 individuals in the group offered PrEP immediately became HIV positive. One of them was found to be positive so early into the study that it is likely he may have seroconverted as he entered the study and thus did not have a chance to benefit from the PrEP. The other two were out of contact with the clinic for extended periods of time and thus unable to renew their prescriptions, suggesting they were not adherent to PrEP usage at the time they were infected.
As previous studies have confirmed, usage of PrEP did not cause users to engage in riskier behaviors. Both groups experienced similar levels of non-HIV sexually transmitted infections, suggesting their behavior did not change if they were using PrEP. As the authors explain, “The preoccupation of some policy professionals with behaviour changes — termed “risk compensation” — was one of the motivations for this pilot study rather than general early access. As with other PrEP studies, PROUD has provided evidence to allay this concern.”
In the other PrEP study, known as Ipergay, found a near-identical reduction in risk for HIV infection of 86 percent. That study included gay men, and other men and transgender women who have sex with men. As in the PROUD study, there were just two infections among those who were using PrEP, and both had discontinued use of the medication several weeks before infection occurred. Among those who were receiving a placebo, infections were much more common, unsurprisingly, for couples not using condoms.
Just this week, the Center for Disease Control and Prevention (CDC) released a new analysis that found that 9 out of 10 new HIV infections come from people who are not receiving care for their HIV. As many of 30 percent of those new infections were transmitted from people who did not know they were infected, a result that jibes with Kaiser Family Foundation’s finding that only 30 percent of gay and bi men have been tested for HIV in the past year. The CDC, along with the World Health Organization, recommends the use of PrEP for anybody who feels they might be at risk of infection.