Vaginal Ring Effective for HIV Infection Prevention

By Ruth Kava — Dec 01, 2016
African women have one of the highest rates of HIV infection in the world. Although some means of prevention exist, compliance has not been great. However, two large, random controlled trials of vaginal rings containing a viral inhibitor, and requiring changing only once every four weeks, suggest that there may be help on the horizon.

Since the 1980s, great strides have been made in designing and producing new drugs to prevent and treat HIV-AIDS.  As a result, HIV infection has become a chronic disease that doesn't progress to life-stifling AIDS, at least in the developed world. Unfortunately, the same isn't necessarily true globally.  In parts of Africa, acquisition of HIV is still a massive problem. Women, in particular, are at high risk of acquiring the infection via sexual intercourse. Although condoms are the most effective non-pharmaceutical means of protection, their use is not under women's control. Prophylactic oral drugs and vaginal gels can also be effective — when used appropriately and consistently, but compliance is not always ideal. Thus, a means of intervention that doesn't require either daily attention or consistent pre-coital use has been devised — a drug-infused vaginal ring that is supposed to last for a month and is under the control of the woman using it. Two programs have been evaluating the efficacy of this means of prophylaxis in sub-Saharan Africa for the past couple of years, and reports of their results have been published in the New England Journal of Medicine.

One study, the Ring Study, evaluated the safety and efficacy of a vaginal ring containing the drug dapivirine which inactivates the HIV-1 virus. This study followed over 1900 women and girls between the ages of 18 and 45 from South Africa and Uganda for up to 2 years. Participants inserted either the drug-containing ring or a placebo ring themselves, and returned to their center every 4 weeks for a replacement ring. Used rings were returned and analyzed to determine how much drug was left. This was a randomized, double-blind study in which participants were assigned in a 2:1 ratio to active drug or placebo.

The second study, the ASPIRE study, evaluated the efficacy of the dapivirine ring in similarly aged women in 15 centers in Malawi, South Africa, Uganda, and Zimbabwe. Again the women were randomly assigned to either active drug or placebo in a double-blinded manner, and in a 1:1 ratio; a total of about 2600 women were enrolled and followed for up to 3 years, receiving fresh rings every 4 weeks.

Both studies demonstrated that the dapivirine ring use decreased the incidence of HIV infection compared to the placebo ring. In the Ring study, the HIV incidence was 31 percent lower in women in the dapivirine group than in the placebo group, and no difference was seen in women over 21 years of age compared to those 21 or younger.

In the ASPIRE study, the incidence of HIV infection was decreased by 27 percent in the treated group compared to the placebo group. Further, in this study, the investigators found that the HIV incidence was greater in younger women (those 21 or less), which they suggested might be due to poorer adherence to the study protocol than in older women. They did not rule out the possibility, however, that there might also be biological differences which might have affected the results.

In sum, these studies go far to confirm the utility of this means of HIV prophylaxis, and give women the means to avoid infection by the virus. Since the utility of any method depends on adherence to its proper use, using a method that requires replacement only once per month will hopefully improve compliance and help stem the HIV-AIDS epidemic in Africa.

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