By: Alanna Shaikh, MPH on February 24, 2016Protecting women from HIV is one of the enduring challenges of the global response to AIDS. The most effective method – using a condom – isn’t a method a woman can chose alone. She is forced to negotiate with her partner to protect herself…every single time they have intercourse. At the same time, women are biologically more vulnerable to HIV infection. Every effective HIV prevention method that a woman can use without needing partner support is therefore a big win in the fight against AIDS.Enter the antiretroviral ring:My precious… (Credit: IPM)It’s a monthly vaginal ring that provides sustained release of an antiretroviral drug. USAID has just announced results from an experimental trial run by the International Partnership for Microbicides (IPM) that found the monthly dapivirine ring safely reduced HIV infection overall by 31 percent compared to a placebo. This matches the results of an NIH study that found similar effectiveness in reducing HIV infections. These are high-quality studies; they had about 2000 participants each in a combined total of 22 locations. The IPM results were actually so promising that they stopped the study early, and women on the placebo will be provided with active dapivirine rings.That’s real news. This is actually the first time we’ve seen anything this successful – we’ve never had two studies back a prevention method like this before. Finding that kind of effectiveness in a once-a-month method that women can use without having to negotiate with a partner is a very big deal.It is not, of course, a magic bullet. When looked at by age group, the data is complicated and frustrating. The ring was less effective with younger users – women ages 18-21 showed no protective effect at all. Users over 25 showed a 61% reduction in infection. This is most likely related to consistency of ring use, but we can’t be certain based on current data. Young women need protection options most of all, so the lack of effect is disappointing.The new ring isn’t going on the market immediately. More research is needed on exactly what kind of product and formulation would have the most impact. For example, a 90-day ring is under consideration. It could also be possible to combine the anti-HIV effect with a contraceptive, providing protection against both HIV and pregnancy. There may also be ways to make the ring more useful to young women; anything from packaging to difficulty of use could be affecting the willingness of young women to use the ring. IPM will be doing that additional research, backed by USAID funding.Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, is somewhat less glowing about the ring than the USAID press release. “This study found that a vaginal ring containing a sustained-release antiretroviral drug confers partial protection against HIV among women in sub-Saharan Africa.” His description is accurate, but it doesn’t go far enough. Protection against HIV in a method that women can insert in advance without needing partner permission – even if it is only partial – is a big step forward in HIV prevention. A step further than we’ve ever made it before.