Kenyan women carry placards during a march to create awareness about HIV and AIDS during World Aids day in the Dandora slums in Nairobi in December. (EPA/Daniel Irungu)

The World Health Organization on Wednesday radically revised its guidelines for those who should be on HIV anti-retrovirals, in a push for early treatment and prevention that it hopes will help end the epidemic by its target date of 2030.

The first major change involves those already infected with HIV. Previously, doctors were to wait until a patient's viral load reached a certain severity before offering treatment. But new studies have shown that treating as early as possible can keep patients healthier and reduce transmission rates with minimal side effects.

The WHO now recommends that anyone infected with HIV begin treatment as soon as possible after diagnosis. That expands the number of people who are eligible for antiretroviral drugs from 28 million to 37 million people around the globe.

The second change involves people who are only at risk of becoming infected. This includes sex workers, people who may have partners who have HIV or who are intravenous drug users. The key words in this new guideline are "substantial risk." In the past, WHO recommended antiretroviral  drugs to prevent HIV acquisition (termed pre-exposure prophylaxis, or PrEP) be offered to men who have sex with men. As a result, AIDS researchers and clinicians tended to consider this treatment as only of those at "high risk."

Now the WHO is recommending that anyone at "substantial risk" should be offered treatment. The change follows the celebrated news last month of the success of a large clinical trial involving the PrEP drug Truvada. In this study, none of the previously healthy participants became infected while on Truvada despite some lifestyle risks. Other studies have shown that Truvada can lower the risk of becoming infected by 80 percent to 90 percent.

A study published by the New England Journal of Medicine showed that men who took the daily antiretroviral pill Truvada significantly reduced their risk of contracting HIV. (Justin Sullivan/Getty Images)

"Following further evidence of the effectiveness and acceptability of PrEP, WHO has now broadened this recommendation to support the offer of PrEP to other population groups at significant HIV risk," the WHO said in a statement.

The new recommendations raise many questions about how the drugs will be made more widely available, one of the most important of which may be who will pay for them.

At about $13,000 a year, PrEP is not cheap. While some state Medicaid programs cover it, others do not, and private insurance companies charge high co-pays for the drug. Gilead, the company that makes the drug, offers a co-pay assistance program, and there are numerous clinical trials in progress that offer the drug for free to participants. HIV/AIDS activists have said the cost has been partly behind the slow uptake in people using the treatment, and they are working to figure out ways to make the drug more accessible.

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