The Pre-exposure prophylaxis (PrEP), which consists of the daily administration of drugs antiretroviral people who are at risk of contracting HIV infection, can be a new and effective preventive strategy against the transmission of the virus.
In a recent study, involving uninfected people and residents in East Africa, whose sex partner was HIV-positive, it has been shown that pre-exposure prophylaxis prevented HIV infection, during a mean follow-up period of one year .
Other previous research on PrEP had obtained very different results ranging from 75% efficacy to no effect. According to Jessica Haberer, of the Center for Global Health at Massachusetts General Hospital (USA) and director of the study, this could be attributed to differences in adherence to medication, adding that her study has precisely shown that PrEP It can be very effective in preventing HIV infection when adherence to the daily dose is high.
At first, almost 5,000 couples - with one of their members infected with HIV and the other healthy - participated in the study, from nine clinical centers in Kenya and Uganda. The uninfected participants were prescribed a daily oral dose of medication, which in some cases consisted of one of the two different formulations of antiretrovirals and, in others, of placebo. In all cases they were informed of the importance of taking the prescribed drug, as well as of other ways to prevent the transmission of HIV.
By the end of the clinical trial only 14 of the uninfected had contracted HIV, and all of them were from the placebo group
A substudy, in which 1,150 couples were included, focused on improving adherence to treatment, and a strict follow-up was established to verify that, in effect, these people complied with the recommended medication protocol, and consisted of home visits without prior notice and to include in the pill bottles a microchip system that registered when they opened.
The average adherence rates to the treatment were 99% in relation to the count of pills in home visits, and 97% if the measurement of the microchip was taken into account. At the end of the clinical trial only 14 of the uninfected participants had contracted HIV, and all of them were from the placebo group, so, according to the authors of the work, the effectiveness of PrEP was one hundred percent.