Scientists have found that a single antiretroviral (ARV) pill used to treat HIV is also effective in helping to prevent HIV infections, a strategy known as pre-exposure prophylaxis, or PrEP.
The US National Institutes of Health said that a once-daily pill containing tenofovir and emtricitabine (which is sold under the brand name Truvada) was safe and provided an average of 44 percent additional protection against HIV infection to men who have sex with men.
The researchers noted that the level of protection varied widely depending on how consistently participants in the study used the pill.
Among those who used the pill on 90 percent or more days, HIV risk was reduced by roughly 73 percent. Those who used the pill less effectively showed much lower levels of risk reduction.
“These results represent a major advance in HIV prevention research. For the first time, we have evidence that a daily pill used to treat HIV is partially effective for preventing HIV among gay and bisexual men at high risk for infection, when combined with other prevention strategies,” said Dr. Kevin Fenton, M.D., Director, CDC National Center for HIV/AIDS, Viral Hepatitis, STD & TB Prevention.
“Given the heavy burden of HIV among gay and bisexual men, a new tool with potential additive benefit is exciting and welcome news,” he said.
The study, which has been published online by the New England Journal of Medicine, was conducted in 11 locations around the world including Cape Town in South Africa, the United States, Peru, Brazil, Ecuador and Thailand.
The drug regime was also found to be effective among transgendered women who have sex with men.
The researchers said that the participants in the study also received a comprehensive package of prevention services that included use of condoms, monthly HIV testing, counselling, and management of other sexually transmitted infections.
They warned that while the results were exciting, it is not time for anyone to stop using condoms or stop following proven prevention methods.
They noted that the the pill does not protect against other sexually transmitted infections and that its use “requires careful adherence, and is an intensive approach that won’t be right for everyone”.
The researchers further advised that PrEP must be obtained from and used in close collaboration with health care providers.