Washington D.C. [USA], Oct. 6 : The anti-HIV drug Truvada has proved to be very effective at preventing new infections when taken by people at high risk, who strictly adhere to the drug therapy regime.

A new study states the cost-effectiveness of this intervention, commonly known as pre-exposure prophylaxis (PrEP) and counts its additional benefits.

Researchers at the St. Michael's Hospital developed a mathematical model to evaluate the impact of PrEP on the number of new HIV infections among gay men in Toronto, the number of HIV-related deaths averted and the cost impact on the health-care system.

Previous studies have found that a daily dose of Truvada could reduce HIV acquisition in men who have sex with men by 44 percent, or as much as 99 percent with high adherence.

The estimated cost of implementing PrEP would increase as more high-risk men use it, from 80 million dollars with 25 percent PrEP coverage to 270 million dollars with 100 percent PrEP coverage.

The author of the study Darrell Tan said, "Putting gay men on preventative therapy could have the added benefit of bringing them into contact with the health care system, meaning they are more likely to be tested regularly for HIV and to have other health issues diagnosed and-or attended to."

Tan and his team found that although testing alone prevented fewer infections than use of PrEP, there was a reduction in cost to the health care system (11,359 dollar per infection prevented) by screening these high-risk patients regularly.

Of the estimated 57,400 gay men living in Toronto, nearly 20 percent have HIV. Despite the availability of anti-retroviral therapy drugs and sustained investments in behavioural prevention programs, rates of newly diagnosed HIV infections and HIV-attributable deaths have not markedly declined in this demographic group in the last 10 years.

"This study makes a strong argument for public reimbursement of this drug. It's more evidence the drug is both clinically and cost effective when targeted at men at highest risk.

A large benefit comes from engaging non-diagnosed HIV-infected men into care," Tan pointed out.

The findings were published online recently in the Journal of the International AIDS Society. (ANI)