The World Health Organization has thrown its weight behind a controversial strategy for curbing the spread of HIV/AIDS: Today the organization strongly recommended that men who have sex with men consider taking a daily pill that prevents infection with the virus.
WHO guidelines are not binding, but can carry considerable sway with governments, which draw on the organization's expertise to determine their national health priorities.
The prevention pill, called pre-exposure prophylaxis, or PrEP, is a combination of two drugs used to treat people with HIV. By taking PrEP daily, an uninfected person can greatly reduce his chances of contracting the AIDS virus from an infected partner.
The pill has already been approved in many countries, including the United States. But it has been dogged by concerns that its benefits could be outweighed by downsides: producing potentially serious side effects in healthy people and encouraging risky sexual behavior.
Rachel Baggaley, an official with WHO's HIV Department, said studies now indicate neither of those worries is warranted. "We have had long follow-up periods, and the rate of adverse events are low," she said. These include impacts on bone density and renal function.
As for how PrEP influences people's sexual behavior, she said, "It's become increasingly apparent that the people who choose PrEP may be the ones who for whatever reasons already have difficulty using condoms. So it's not causing less condom use."
The pill is expensive in the United States, where the drug alone costs over $10,000 annually, without counting add-ons such as the regular HIV testing and monitoring for side effects that it requires.
However, increasing numbers of insurance companies are agreeing to cover PrEP. And the company that makes the pill, Gilead Sciences, has begun licensing its manufacture in lower income countries like South Africa and India, where HIV/AIDS is more prevalent. As a result, the cost of PrEP there is down to about $100 a year or 25 cents a day. That's on par with the cost of treating someone who is HIV-positive in those countries, and Baggaley said the pill could prove a cost-effective solution for many of them. WHO officials estimate that PrEP use among gay men over a 10-year period could reduce HIV transmission by 20 to 25 percent or 1 million new infections worldwide.
The U.S. Centers for Disease Control and Prevention cited similar findings in May when, for the first time, it recommended PrEP for gay men it considers at "substantial risk" for HIV. The CDC defined this as gay men who, over the past six months, have either been diagnosed with a sexually transmitted disease or had anal sex without a condom.
WHO's recommendation is more general citing all men who have sex with men. Baggaley said the organization will develop more detailed guidelines in the coming months.
The guidelines released today are part of a larger shift in WHO's approach to HIV prevention as the organization homes in on several key subgroups where the effort has been less successful. These include not just gay men, but people who inject drugs, people in prisons, sex workers and transgender people. Rates of HIV infection remain very high among these groups, even as they have declined for the overall population of countries where the AIDS crisis has been most severe. WHO is weighing whether to extend its strong recommendation of PrEP to them as well.
"We recognize that the AIDS epidemic is changing," said Baggaley. "In countries like Ghana, or Kenya or Nigeria, where it was once generalized, now more than 30 percent of new infections are among these key vulnerable populations."
Yet, she noted, these same groups are the most likely to be missed by existing government programs or worse, singled out by governments for discrimination and abuse.
WHO hopes the latest guidelines will serve as a wake-up call to make it a priority to prevent HIV among the most vulnerable populations.