Antiviral Vaginal Ring Effective in Preventing HIV in African Trial

In a finding that could help stop the spread of the human immunodeficiency virus (HIV) — particularly in Africa – researchers found that women who use a vaginal ring containing an antiretroviral drug, such as dapivirine, are about 30% less likely to contract HIV-1.

The study was conductedy Jared M. Baeten, MD, PhD, of the University of Washington in Seattle, and colleagues and were published in the New England Journal of Medicine February 22, 2016.

Study participants were enrolled between August 2012 and June 2015, from sites in Malawi, South Africa, Uganda, and Zimbabwe.

There are 37 million diagnosed with HIV/AIDS in the world and about half live in Africa, so the search for an easy-to-use preventive has been a goal for decades.

The study subjects were women ages 18 to 45, who were not pregnant, tested negative for HIV-1, and who were both healthy and sexually active. There were a total of 2629 women enrolled; 1313 received dapivirine and 1316 received a placebo during the course of the trial. The participants underwent monthly follow-up visits and were tested for HIV-1, pregnancy, and received adherence counseling. During each monthly visit they returned the used ring and received a new one.

Nearly all of the participants (99.4%) completed at least one follow-up HIV-1 test, and the median follow-up was 1.6 years. The researchers report, “Across all 15 sites in the trial, a total of 168 incident HIV-1 infections occurred during the product-use period: 71 in the dapivirine group and 97 in the placebo group.”

In addition to showing that a vaginal ring with dapivirine offers some protection from HIV-1, researchers found that adherence was greater than in previous studies. The researchers caution, “our definitions could have led to an overestimation of adherence because participants were categorized as being adherent even though they may have used the ring for only a portion of the month.”

This study is important because, as the researchers note, “African women bear a disproportionate burden of the global HIV-1 epidemic.”

In fact, in the placebo group in this trial, the researchers found “the annualized HIV-1 incidence was more than 4%, despite monthly HIV-1 testing and risk-reduction counseling, testing of male partners, screening and treatment of sexually transmitted infections, and provision of free condoms.” If women are more willing to use a vaginal ring that offers protection, the rate of infection could be lowered.