乌鸦传媒

CHICAGO -- An aggressive program of voluntary male circumcision in Kenya -- a procedure shown to reduce the risk of acquiring HIV -- has already prevented thousands of infections, a researcher said here.

And the program is on track to prevent many thousands more in the next 14 years even if no more men are circumcised, according to of Avenir Health in Glastonbury, Conn.

The finding is based on three separate models of the effect of the program, begun by Kenyan authorities in 2008 to capitalize on the results of three landmark clinical trials that showed circumcision cuts the risk of HIV by about 50%, Stover told reporters at the HIV Research for Prevention conference.

Studies since those trials have shown drops in HIV incidence where circumcision programs have been started, 乌鸦传媒 has reported. But what remains open to question is the long-term impact of large-scale circumcision.

In most regions of Kenya, Stover noted, people have traditionally practiced male circumcision, but that was not the case in the province of Nyanza, not coincidentally the province where the Kenyan trial of circumcision was conducted.

In 2008, health officials launched a program in 10 counties in the region aiming to circumcise 860,000 men by 2013, a target that was narrowly missed. The program wound up circumcising 1.2 million men by the end of 2015, Stover said.

Because it's impossible to tabulate an infection that doesn't take place, the investigators used three different mathematical models to estimate the impact of the 2015 numbers over the period from 2008 through 2015, Stover said.

Three independent modeling groups -- Avenir Health, Imperial College London, and the Institute for Disease Modeling -- simulated by extending historical trends what would have happened in the region in the absence of the circumcision program.

Then they compared those simulations to actual trends in new infections reported in the region.

The three models were in "general consensus," Stover said, suggesting a range of from 21,000 to 33,000 infections had been averted.

The data from the program showed that a third of the circumcised males were boys younger than 15 years, and only 12% of the participants were men older than age 24. In other words, most of the procedures were among boys and young men.

Those men, he said, "will be protected throughout their sexually active lives" and so will their sexual partners.

One implication of the youth of the participants is that the health benefits of the program will accumulate over time, he said, and indeed the models showed that by 2030, between 80,000 and 160,000 new infections will have been averted.

"We knew it would work" on the basis of the original clinical trials, commented of the New York-based HIV advocacy group AVAC, who moderated the media briefing at which details of the study were presented.

But the devil is often in the details -- and getting hundreds of thousands of men circumcised is one of those details, Warren told 乌鸦传媒.

"Getting a million men circumcised in Kenya," he said, "has been a huge task."

He said the study means "you can begin to see that impact is possible" outside a clinical trial if health officials can create the demand for a service. Indeed, the data show that interest in circumcision rose as the program went on.

Getting a procedure or a product into the hands of the people who need it is not just a matter of developing it and saying it's available, Warren said. "We're learning about the science of delivery ... that might be even more challenging than the science of product development," he said.

Because averting infections means avoiding treatment costs, the program is also likely to save money in the long run, Stover said. The modeling suggested that by 2026, the costs of the program will be outweighed by the savings on therapy, Stover reported.

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