The findings, reported on 17 July in the British medical journal, The Lancet, emerged from a clinical trial in Rakai District, southern Uganda, involving 922 HIV-infected men and 163 of their HIV-negative female partners.
Half the men were circumcised at the start of the two-year trial; the other half, who made up the control group, were circumcised at the end of it. Their uninfected female partners were followed up after six, 12 and 24 months to determine whether they had acquired HIV from their male partners.
Male circumcision has become a recommended HIV-prevention strategy since three clinical trials, one of which was also held in Rakai, showed that the procedure could reduce the HIV risk to men by as much as 60 percent. Until now, little was known about whether male circumcision also reduced the risk of HIV infection in women.
Previous observational studies suggested that the partners of circumcised HIV-infected men were less likely to acquire HIV, but the trial in Rakai failed to confirm this. Out of 92 couples in the circumcised group, 18 percent of the women became infected during the study period, compared to 12 percent of women in the uncircumcised control group.
Male circumcision may actually have increased the HIV risk to some of the women in the intervention group. After six months, women whose partners ignored advice to abstain from sex for at least six weeks after the circumcision procedure had an HIV acquisition rate of 27.8 percent, compared to 9.5 percent among women whose male partners delayed sex until healing was complete, and 7.9 percent among women with uncircumcised partners.
The trial was stopped early because of "futility", meaning that the accumulation of further data was unlikely to produce substantially different results.
The findings are likely to have important implications for the male circumcision programmes being rolled out in a number of countries with high rates of HIV, including Zambia, Swaziland, Kenya and Uganda. The programmes have received substantial backing from governments, international donors and UN agencies.
In an accompanying comment in The Lancet, Jared Baeten, of the University of Washington's Departments of Global Health and Medicine, cautioned that the results of the Rakai trial "should in no way hinder programmes working to scale up circumcision services for men at risk for HIV".
Circumcising HIV-positive men may not directly reduce HIV risk to their female partners, but large-scale male circumcision programmes would benefit women in the long term by bringing down overall HIV prevalence in communities.
Baeten also agreed with the study authors that the results should not prevent HIV-infected men from qualifying for the procedure, because excluding them could lead to stigmatization and deny them other health benefits, including a reduction in genital ulcer diseases.
The findings reinforced the need for men undergoing the procedure to receive extensive counselling about the importance of delaying sex for at least six weeks afterwards, the continued need to use condoms, and to reduce partner numbers.
See also: AFRICA: Mass male circumcision - what will it mean for women?
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