A vaginal ring coated with an anti-AIDS medication — inserted once a month — partially protected women against HIV infection, reported researchers Monday as they released the results of two large studies in Africa.
While the protection it offered was modest and reduce overall HIV infection by less than one-third, the ring emerged as safe and surprisingly worked better in women ages 25 and above. Researchers were left to wonder if younger women simply did not use it properly to obtain little to no benefit.
"This is the first demonstration of a sustained-release approach for HIV prevention," said University of Washington's Dr. Jared Baeten, who led one of the two studies.
Dr. Baeten also told reporters that he wants "rings, pills and other strategies to be on the shelf for women" to help them make HIV prevention choices that will work for them. Current options include a daily anti-AIDS pill or "pre-exposure prophylaxis," which unfortunately are as widely accessed in poor countries like African nations.
Women are more than half of the almost 37 million sufferers of HIV worldwide, and most of them are in Africa. Experts are seeking protective tools for them when their partners would not wear a condom.
The two studies, presented at the Retrovirus Conference in Boston, involved more than 4,500 women in Africa and compared those who used the dapivirine ring with those given a similar-looking yet drug free variety. The ring was found to reduce the subjects' overall HIV risk by 27 to 31 percent.
The ASPIRE study, a large one funded by the National Institutes of Health and led by Dr. Baeten, turned up rather surprising results: ring wearers who were 25 years and above were 61 percent less likely to get infected, while those in the 18 to 21 age group receive practically no benefit.
The lead author said that there are signs of irregular use among the younger women, therefore reaping not as much benefit as those who used the vaginal ring continuously in the study, which lasted two and a half years.
The second study dubbed as the Ring study also showed greater protection for women above age 21.
Despite mixed results — or modest protection yet the question of whether women can use the product correctly and effectively — nonprofit group International Partnership for Microbicides said it considered the study results sufficiently promising to apply for regulatory approval for wider distribution in Africa.
The study is also yet to be completed but South African authorities have asked for all the remaining subjects to be shifted to the dapivirine ring from the placebo, the IPM added.
The age disparity, however, has prompted the NIH to start consulting with external experts on the next research steps to follow.
In the United States, vaginal rings are sold as a birth control mechanism. Africa's anti-HIV version, however, contains no contraceptive component.
The study was published in the New England Journal of Medicine