There may be a promising new way to help prevent HIV in women. Two studies presented Monday demonstrated the effect of a vaginal ring as a way to deliver medication that can prevent HIV transmission.

In one study, published online in the New England Journal of Medicine, women over 21 who were given the ring had a 27 percent lower incidence of HIV than women given a placebo ring with no medication. The second study, presented Monday but not yet published, had similar numbers, with 37 percent fewer infections in women over 21 who were given the ring with medication.

The ring works by releasing a chemical called dapivirine which interferes with how HIV replicates.

Researchers have been looking into this ring method for more than two decades as a potential way for women to prevent HIV transmission. Studies have shown that other preventative HIV measures, such as pills and vaginal gels, have not been successful in decreasing HIV rates in sub-Saharan countries including South Africa, Uganda and Tanzania, and researchers think a big problem with both these methods was adherence, or sticking to a regular routine of taking the medication.

This is especially important with preventative treatments like birth control pills, which have to be taken consistently every 24 hours for the preventative effects to work. Of the 35 million people currently living with HIV, half are women, with the majority living in sub-Saharan countries in Africa.

The study, which took place in Malawi, South Africa, Uganda, and Zimbabwe and was funded by the National Institutes of Health, enrolled more than 2,600 women, with half getting the ring with dapivirine and the other half getting a placebo ring. From August 2012 to June 2015, the women came in monthly to be tested and given a new ring.

Physicians also tested the women's blood to see how much of the ring's active ingredient was actually in the bloodstream. This way, they could tell if it had been removed and simply replaced for the checkup.

Using this method, their findings suggested that women aged 18-21 had the toughest time adhering fully to the medication, but among those 21 and older, adherence tended to be rather high - about 70 percent.

By the end of the two-year study period, 168 participants had contracted HIV. While 97 of those women had been in the placebo group, 71 had been in the medicated ring group. That translates into a 27 percent lower infection rate for women who who were given the new medicated ring.

While 27 percent might not be an ideal success rate, it does bode well for having the ring as an option for women who have trouble taking a daily pill. Another promising observation was that after the first month, adherence increased, which the researchers suggested could have something to do with getting more comfortable with the ring.

This article was originally published by Business Insider.

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