Studies in Africa show AIDS drugs may reduce HIV infection

Two US studies carried out in Africa suggest that AIDS drugs used to treat HIV may dramatically reduce the risk of infection among heterosexual couples it was announced on Wednesday.

The research involving couples in Kenya, Uganda and Botswana found that daily AIDS drugs reduced infection rates by an average of at least 62 percent when compared with placebo.

Prevention tools
"Effective new HIV prevention tools are urgently needed and these studies could have an enormous impact on preventing heterosexual transmission," Margaret Chan, director-general of the World Health Organization (WHO), said in a statement.

The US Centers for Disease Control and Prevention plans to review the data and issue its own guidelines - taking into account issues such as whether behavior may change when people know they are taking a drug that reduces infection risk, said Dr. Jonathan Mermin, CDC director HIV/AIDS prevention.

In its first official guidance on the topic, the CDC said in January that only high-risk gay and bisexual men should use a daily AIDS pill to protect themselves from the virus.

Discordant couples
The larger of the two new studies examined 4,758 "discordant" couples in Kenya and Uganda in which one partner was HIV-positive and one was negative. Those negative partners taking Gilead Sciences Inc's tenofovir, or Viread, had on average 62 percent fewer infections.

For couples on Truvada - another Gilead drug combining tenofovir and emtricitabine - the infection risk was cut by an estimated 73 percent in the clinical trial, which was led by researchers at the University of Washington.

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Daily Truvada
The second study, involving just over 1,200 sexually active men and women in Botswana, found those on daily Truvada reduced their risk of HIV infection by 62.6 percent.

Lead investigator, Dr. Michael Thigpen, said Truvada proved to be safe and effective. He said the drug - along with things like male circumcision, topical microbicide gels and condoms - could be another tool for preventing the spread of HIV.

The idea of such "pre-exposure prophylaxis," known as PrEP, has gained traction in the past year, following results of other research showing a fall in infection rates among gay men taking AIDS drugs.

However, PrEP took a knock earlier this year when another study failed to demonstrate a protective effect in high-risk women. The latest strong evidence is likely to restore confidence in the approach.

Effective approach
Around 33 million people worldwide have the human immunodeficiency virus (HIV) that causes AIDS, most living in Africa and Asia. Only about half know their HIV status, and the WHO hopes that news of an effective approach to prevention will encourage more people to get tested.

Source: Reuters