- Category: HIV Sexual Transmission
- Published on Thursday, 22 December 2016 00:00
- Written by HIVandHepatitis.com
Use of Truvada for pre-exposure prophylaxis (PrEP) is highly effective and is now widely used among gay men, but biomedical HIV prevention for women has lagged behind.
Large trials have found that oral PrEP does not work as well for women as it does for gay men. Part of the reason is low adherence, but biological factors also play a role. Studies this year showed that tenofovir and emtricitabine -- the drugs in Truvada -- reach lower levels in vaginal compared to rectal tissue and vaginal bacteria may both increase susceptibility to HIV and reduce PrEP effectiveness.
Prevention methods other than daily pills may work better for some women. In apair of studies presented at the Conference on Retroviruses and Opportunistic Infections, vaginal rings containing the NNRTI dapivirine demonstrated only moderate efficacy overall (around 30%). But they were more effective among women over age 25, reducing the risk of HIV infection by around 60%. Another type of ring that releases tenofovir and emtricitabine maintained protective drug levels over 4 months and prevented infection in a monkey study.
Further studies of vaginal rings are underway, along with other types of prevention tools that may better fit into at-risk women's lives.