Ringing the changes

PLENTY of progress has been made in the fight against AIDS. Deaths peaked in 2005, at around 2m people. By 2015 that number had fallen to 1.1m. One big reason is that, of the 36.7m people currently infected with HIV, 18.2m are taking antiretroviral drugs that can hold the virus back for decades. Their number has risen more than twentyfold since the turn of the century.

But not all the statistics are so encouraging. Around 1.9m adults contracted HIV in 2015. That number has hardly budged since 2010. The great bulk of those infections, about 1.3m in 2015, happen in sub-Saharan Africa. They happen more often to women than to men: 58% of HIV-infected people in the region are female. Women between 15 and 24 are infected at almost eight times the rate of men of the same age.

There are several reasons why women contract HIV more often than men. Some are biological: women have a higher chance of contracting HIV from a given act of unprotected sex than men do. But cultural factors matter too, especially in poor countries. As in other aspects of society, it is often men who call the shots in the bedroom. Even if a woman wants a sexual partner to use a condom, she may struggle to convince him to do so.

On May 3rd, a charity called the International Partnership for Microbicides (IPM) announced a clinical trial that it hopes could help the situation. It has developed a small silicone ring designed to be inserted into the vagina, from where, for the next three months, it releases steady doses of dapivirine and levonorgestrel. The first of those is an anti-HIV drug. The second is a contraceptive.

IPM’s device builds on a previous model that contains only dapivirine. Two big clinical trials of that device concluded in 2016 and showed it could reduce the risk of catching HIV by about a third. That may not sound particularly impressive. But Zeda Rosenberg, IPM’s founder, says this number almost certainly represents only a floor on the treatment’s effectiveness. “We know from the trial results that not all the women used the ring consistently,” she says. Those that did will, she thinks, have enjoyed substantially better protection.

Combining an anti-HIV drug with a contraceptive may give women a reason to use the product more faithfully. Dr Rosenberg points out that in societies that expect women to be demure or chaste, those who take steps to protect themselves from HIV can often face stigma, since others may assume they are engaging in risky behaviour. But no such stigma applies to contraception. In any case, the ring is small and unobtrusive enough that women can wear it without their partners’ knowledge.

The first trial is designed only to demonstrate that the ring is safe, and will be conducted in America. Later tests will check how well it works, though the fact that the dapivirine-only ring has already passed similar tests should speed that process. IPM hopes to have the first batch of dual-purpose rings ready for shipping by 2020. If there is demand, it might even offer the rings for sale in the rich world, in the hope that the cash so generated could cross-subsidise production for poor countries where the need is greatest.