PARIS (AFP) - The systematic circumcision of all boys in sub-Saharan Africa could potentially prevent nearly six million new HIV/ AIDS infections over the next two decades, a research team says in a published study.

The study, coordinated by Brian Williams of the World Health Organization (WHO) and published in the US review PLoS Medicine, is based on results of a trial conducted in South Africa, in which men were offered the chance to be circumcised. Those who chose to be circumcised had a lower HIV infection rate 18 months later.

Researchers say that their test shows a reduction in rates of infection, from women to men, of about 60 percent. Extrapolated mathematically, that would lead to a prevention of about two million new HIV infections in the next 10 years, and a further 3.7 million cases in the decade after that, while 2.7 million deaths could be prevented.

About a quarter of those numbers, both deaths and infections prevented, would occur in South Africa, they said.

The study builds on primary research led by co-author Bertran Auvert of France's Inserm medical research institute in the Orange Farm area of South Africa.

His group's work on 3,000 male cases provided a scientific demonstration of previous speculation that male circumcision could have an impact on the spread of AIDS, which is ravaging Africa.

Results from other trials in Uganda and Kenya are being gathered by the US National Institutes of Health (NIH), and are expected to be published in September 2007.

Some 38.6 million people are dealing with HIV or AIDS, some 24 million of them in Africa.