As men in a region of Uganda have adopted medical circumcision, the population level incidence in HIV dropped markedly, a researcher said here.

The finding comes from the region of Rakai, where circumcision has been offered as a service since a landmark clinical trial there showed the procedure reduced the risk of infection, according to Ronald Gray, MD, of the Johns Hopkins School of Public Health in Baltimore.

Among non-Muslim men, the rate of male circumcision had risen from about 5.6% in the years 2000 to 2003, before the clinical trial started, to 25.3% in 2009, Gray told reporters at the annual Conference on Retroviruses and Opportunistic Infections (CROI).

Correspondingly, he said, the incidence of HIV among those men - whether circumcised or not - fell from 1.36 per 100 person-years in 2000 to 2003 to 1.05 per 100 person-years in 2004 to 2009.

The incidence rate ratio was 0.78, with a 95% confidence interval from 0.62 to 0.98, and was significant at P=0.04, Gray reported.

Analysis of HIV incidence among Muslim men, who are circumcised at birth, showed no change over time, suggesting there is no secular trend that might explain the difference among the non-Muslims, he said.

There was also no change in the incidence rate among women in the region, he said.

The finding is “very good news” for those interested in HIV prevention, commented Sharon Hillier, PhD, of the University of Pittsburgh, who was not part of the study but who chaired a CROI press conference at which details were presented.

It turns out that “less is more in terms of male protection,” Hillier quipped during the presentation.

Later, Hillier told MedPage Today that the results are not surprising - a similar study carried out in South Africa and reported last summer also found a marked population-level impact of circumcision.

But “it’s a story that doesn’t get told enough,” she said. “This is an intervention that can be done one time and gives years of benefit.”

Gray told MedPage Today the results from the Rakai region and those from South Africa are “pretty comparable.”

In that study, researchers led by Bertran Auvert, MD, PhD, of the University of Versailles in France, found that circumcision in the region of Orange Farm, near Johannesburg, had become popular after the end of a second clinical trial that showed it reduced the risk of HIV.

Auvert told MedPage Today at this meeting, “we are changing the social norm” in Orange Farm, to the point that “all the young guys would like to be circumcised.”

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Primary source: Conference on Retroviruses and Opportunistic Infections
Source reference: Gray R, et al “Population-level impact of male circumcision on HIV incidence: Rakai, Uganda” CROI 2012; Abstract 36.