In two phase III trials conducted in Sub-Saharan Africa, the monthly ring – which slowly releases an HIV-fighting drug, Dapivirine – reduced infection rates overall by about 30 percent.
The Ring Study safely reduced the infection rates by 31 percent of 1,959 enrolled woman ages 18-45, compared to the placebo. While the ASPIRE trial, which was published in the New England Journal of Medicine, lowered the rate of infection by 27 percent among women in the same age range.
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The Dapivirine ring is the first long-acting HIV prevention method designed for women.
"Women need a discreet, long-acting form of HIV prevention that they control and want to use," Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases, said in a press release.
Both studies saw significant differences in effectiveness according to age with the ASPIRE study resulted in a 61 percent reduction in women older than 25 likely because of their consistency to use the product compared to younger women. And Fauci confirms, "Further research is needed to understand the age-related disparities in the observed level of protection."