Public Health

Vaginal Ring Protects Monkeys From HIV-Like Infection

A small, plastic vaginal ring loaded up with an HIV drug protects monkeys from infection with simian immunodeficiency virus.

A small, plastic vaginal ring loaded up with an HIV drug protects monkeys from infection with simian immunodeficiency virus. Julie Sitney/Courtesy of the Population Council hide caption

itoggle caption Julie Sitney/Courtesy of the Population Council

When it comes to contraception, women have many options. There are pills, patches, diaphragms and even a vaginal ring that slowly releases birth control hormones.

For preventing HIV, however, the options are limited. Woman can wear a female condom, or for partial protection, they can take a daily pill that was just approved by the FDA.

Now an animal study just published in Science Translational Medicine suggests that the vaginal ring holds promise as a new way for women to protect themselves against HIV.

A team of chemists have developed a small plastic ring that significantly reduces the risk of infection when monkeys are exposed to SHIV, a version of simian immunodeficiency virus that also carries HIV genes. Although the study is small— and it is unknown how the findings will translate to humans — the results raise hopes that an ongoing clinical trial with a similar ring will be successful in people, too.

To create a device to stop HIV infections, Thomas Zydowsky and his colleagues at the nonprofit Population Council replaced the hormone in the ring with an antiretroviral drug.

They had to tweak the composition of the ring so that it works with the drug, but they eventually found a design that reduces the rate of SHIV transmission in macaques monkeys from about 80 percent to 12 percent.

The researchers concede they don't know precisely how this result in monkeys relates to people. "There are no studies correlating protection in macaques with that in humans," Zydowsky tells Shots. "The success of the animal study just gives us a better feeling that the ring will work in people."

Other scientists seem confident about the method's potential. The National Institutes of Health launched a clinical trial last July with another ring that also releases an antiretroviral drug. The study is testing the device on nearly 3,500 women across Africa, and they hope to have results by early 2015.

Other trials that focused only on gels have had mixed results. Zydowsky says this may be because the gels are tough to use. They must be applied both before and after sex.

The ring, on the other hand, worked just as well in the monkeys when it was inserted 2 weeks or 24 hours before exposure to the virus. And, this seems like a big advantage to the rings. "Woman can put it in and than just forget about it," Zydowsky says.

Right now woman make up more than half of HIV-positive people in the world, and they are twice as likely to contract HIV during sex than men. So, if vaginal rings can be proved safe and effective, they could become popular options for HIV protection someday.

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