HIV prevention in women using a wearable ring
Around the world, close to 40 million people are living with HIV, most of them in poorer countries. But in recent years there have been encouraging results from a drug-impregnated ring that's inserted into the female genital tract, showing that it can cut HIV infection rates by 50%. It's made of a soft silicon material, and a new version of the device that has recently been designed and tested for safety can remain in place for up to 90 days at a time, where it steadily releases a cargo of the anti-AIDS drug dapivirine. It could make a big difference to the autonomy of women in poorer countries, which have been hard hit by HIV in the past few decades. Public health researcher Albert Liu has just presented the latest performance and safety results at a conference, as he told Chris Smith...
Correction: The original publication of this interview indicated that the 90-day ring cuts infection rates by 50% - this is still unknown, the monthly ring has been shown to cut infection rates by 50%. This recent study tested pharmacology and safety exclusively.
Albert - Women make up more than half of all people living with HIV and they need a range of strategies to prevent HIV infections. One promising approach to HIV prevention is the use of vaginal rings, which are really exciting because they offer a long acting prevention approach to preventing HIV.
Chris - Now, when you said that women make up more than half of cases, why are they disproportionately impacted by HIV then?
Albert - In Sub-Saharan Africa, it may be unequal relationships with men, as well as some women engage in sex work and may have less economic opportunities. And there may also be some biological differences that make women more susceptible to HIV.
Chris - And the approach that you're testing here - tell us how it actually works then. What does it do? And how does it protect the user?
Albert - The vaginal ring that we have been studying was developed by a non-profit group, the International Partnership for Microbicides. They've developed a ring that contains a medication called dapivirine. It's an anti-HIV medication that is dispersed into the ring and releases the drug slowly into the vagina. This medication prevents infection taking place in the body.
Chris - And does it actually work? Is that what you're finding?
Albert - There were two large studies in over 4,500 women in Africa and they found that the ring was both safe and effective in reducing HIV infections. The latest studies that were done suggest that the ring reduced HIV infections by about 50%.
Chris - Why is this better though than just popping a pill? Because we could give this same drug in pill form, which arguably might be even easier to distribute.
Albert - Yeah. The pill form of prevention also known as PREP or pre-exposure prophylaxis is a really important and exciting option for HIV prevention. But what we've seen across a number of studies is that oral PREP is not for everyone. There may be a number of reasons why women may prefer not to take a daily pill. It can be challenging for people to remember to take the pill every day. Also the pills need to be kept private and that can sometimes be a challenge. So there needs to be a range of options for women to be able to choose different options that will work the best for them.
Chris - And is the strategy then that the women insert these rings and keep them inside for the full lifetime of that ring, or do they take it in and put it out on a daily basis? How does it work?
Albert - The ring is designed to be inserted and remain in place for the duration of use. And so for the monthly ring that's for a whole monthly period.
Chris - You've got a ring here which has got just one drug in it. Is that not a risk though that we're going to end up with the next scourge of HIV being resistant to that drug? And it will just therefore surmount the protection conferred by these rings, and people are going to catch HIV anyway?
Albert - That was looked at in several of the earlier studies, they looked at women who became HIV positive in the studies, and they did not see development of HIV resistance as a result of use of the ring.
Chris - How is this going down with the users?
Albert - Women have reported that the ring is very easy to use and also neither they nor their partners could feel the ring during sex. And they liked this option as a prevention strategy.
Chris - And impact on fertility? Is there any impact on likelihood of conception? Are these drugs considered completely safe if a person does fall pregnant while they are using this particular method?
Albert - There isn't evidence that these rings affect fertility. We are currently doing a study of ring use during pregnancy and it's a really important study because women during pregnancy are particularly vulnerable to acquiring HIV.