A vaginal ring infused with an antiviral drug appears to offer protection against HIV infection, although not as much as doctors had predicted. Women who used the ring had a 27 percent lower risk of HIV infection than women who received a placebo, scientists reported February 22 in the New England Journal of Medicine. A second separate study had similar results, finding a 31 percent reduction. Both studies were released during the annual Conference on Retroviruses and Opportunistic Infections in Boston, Mass.
The trials, conducted by international teams of researchers, involved women in sub-Saharan Africa, a region hard-hit by the epidemic. Public health officials hope that discreet, long-lasting protection will help women protect themselves from infection (SN: 11/14/15, p. 14).
The vaginal ring delivers the drug dapivirine, and lasts for a month. The larger of the two studies, called ASPIRE, involved 2,629 women who were randomly assigned to use the ring or a placebo. After a median follow-up of 1.6 years, 71 women using the ring became infected, compared with 97 women using a placebo. Although overall the ring was modestly successful, the study’s authors note a number of complicating factors. For one, women from two of the 15 study sites had low rates of adherence; when the data are analyzed without those sites, infection rates were 37 percent lower among women who used the ring. Also, the ring was less protective among women younger than 21, a finding also correlated with lower consistent use.
The second study, called The Ring Study, enrolled 1,959 women in South Africa and Uganda. The results of that study were released early, following a decision to close the placebo arm in South Africa and offer the ring to any woman participating
Since the ring is not yet on the market, “real world” results remain to be seen. Previous research has found that adherence to oral HIV prophylaxis often increases when studies are not randomized and participants know they are actually getting the drug.