[NAIROBI] A man's risk of contracting HIV/AIDS during heterosexual intercourse can be halved if he is circumcised, results from two major trials in Kenya and Uganda show.
But five top UN agencies warn people not to engage in high-risk behaviour, such as not using condoms during sexual intercourse.
The results of the trials were announced this week (12 December) by the US National Institutes of Health.
They confirm a South African study published in November last year that showed a 60 per cent reduction in HIV infection among circumcised men (see 'Male circumcision could save millions from HIV/AIDS').
According to the co-leader of the Kenyan trial, Stephen Moses of the University of Manitoba in Winnipeg, Canada, there were 22 new HIV infections among circumcised men in the study, compared to 47 among the uncircumcised men. This represents a reduction of 53 per cent.
"We now have conclusive data showing male circumcision reduces the risk of HIV acquisition in men," he said.
The Kenyan trial involved 2,784 HIV-negative men between the age of 18 and 24 in Kisumu, western Kenya.
The trial in Rakai, Uganda, in which 4,996 healthy men took part, showed that HIV infection was reduced by 48 per cent in circumcised men.
Both trials were terminated early as preliminary data showed that medically performed circumcision — the surgical removal of the foreskin of the penis — to be safe and effective at reducing HIV infection.
Researchers in Kisumu said plans are now underway to circumcise all men in the study group. "The results were so overwhelming that the operations will start on 15 December, as not to do it would be unethical," said Kwango Agot of the University of Nairobi, Kenya, a senior programme officer at the study centre.
AIDS experts have welcomed the news. Daniel Halperin, an HIV specialist at the US-based Harvard Center for Population and Development, said, "when word of this gets around, millions of African men will want to get circumcised, and that will save many lives."
Agot explained that uncircumcised men are at higher risk of contracting HIV because the foreskin is rich in sentinel cells of the immune system and attach easily to HIV. "The foreskin sometimes ruptures during intercourse," he said.
However, five top United Nations agencies — the World Health Organization, UN Population Fund, Joint UN Programme on HIV/AIDS (UNAIDS), UN Children's Fund and the World Bank — are giving the news a guarded welcome.
In a joint statement released yesterday (14 December) they announced their plan to draw up guidelines to prevent people from engaging in 'high-risk behaviour', such as not using condoms during sexual intercourse.
"Circumcised men can still become infected with the virus and, if HIV-positive, can infect their sexual partners," said the statement.
The agencies said circumcision should never replace other known, effective preventive methods and should be considered as part of a comprehensive prevention package (see 'The dangers of promoting male circumcision against HIV/AIDS').
UNAIDS announced that a further trial to assess the impact of male circumcision on the risk of HIV transmission to female partners is underway in Uganda, led by scientists from Johns Hopkins University in Maryland, United States. The results are expected in 2008.
An estimated 30 million people in sub-Saharan Africa are infected with HIV/AIDS. More than 90 per cent of HIV infections in adults result from heterosexual intercourse."In Kisumu, the third-largest city in Kenya, an estimated 26 per cent of uncircumcised men are HIV positive by the age of 25," says Moses.