Although circumcision programmes will involve significant initial costs, they will save billions of dollars in the long-term, according to a mathematical model presented to the Sydney International AIDS Society Conference on July 25th.
A separate mathematical model also presented to the conference, showed that universal circumcision would have the greatest impact on HIV incidence, but that targeting circumcision at men with the most sexual partners, and those aged between 20 – 30-years would be the most effective way of reducing HIV prevalence.
The rapid roll out of circumcision as an HIV prevention measure would require high uptake and substantial funding in the first few years if it is eventually to be cost-effective, according to a costing model developed by French circumcision researcher Bertran Auvert and colleagues in France, South Africa and the United States.
Using demographic data from 14 African countries with a circumcision prevalence of less than 80% and adult HIV prevalence of more than 5%, the researchers modelled the cost for individuals and the public sector of a rapid roll out of medical circumcision for adult males.
The cost was calculated over a ten year period, and then adjusted to take into account the amount the researchers estimate would be saved if HIV infections were averted and antiretroviral therapy was not needed.
Rolling out circumcision in the 14 countries would cost the public sector between $315 and $532 million during the first five years, but a much greater cost would be borne by the private sector, particularly by individuals paying fees for circumcision operations. Private expenditure on circumcision might top $1.2 billion.
Although considerable investment would be required in the first five years of a circumcision roll-out programme, Dr Auvert calculated that over 20 years between $3 - $4 billion would be saved in HIV treatment and care costs.
Dr Auvert also calculated that the cost of circumcision per infection prevented would be between $113 - $375 and that, in the first 20 years, it would be necessary to circumcise between four and nine men to prevent each new HIV infection.
Although Dr Auvert acknowledged that the costs of a mass circumcision programme would be “expensive”, it would ultimately be worth the cost given the long-term savings in treatment and care costs.
Modelling data on the effects of circumcision on HIV prevalence and incidence between now and 2020 were also presented, by Gregory Londish of the University of New South Wales, Sydney.
His simulations predict that complete male circumcision in an average country could reduce HIV prevalence in 2020 from 8.3% to 5.3% and incidence from 13.5 seroconversions per thousand to 7.3 per thousand.
Targetting only 20 to 30 year old men or men with greater sexual activity produced the most cost-effective reduction in HIV prevalence, 2.0% and 1.1% respectively.
But the benefits would be smaller with increasing sexual activity in men who have been circumcised, and would be completely eliminated if more than 40% of circumcised men increased their sexual activity.
Another sophisticated model, developed by Timothy Hallett of Imperial College, London, presented at last month’s 2007 HIV Implementers’ Meeting in Kigali, Rwanda, highlighted the uncertainties inherent in current assumptions about circumcision’s efficacy.
He pointed out that although all three randomised studies of circumcision had shown a similar efficacy for the intervention – around 60% - the confidence intervals for the efficacy estimates were wide.
“If 60% represents the upper bound of effectiveness, once you get down to 40% efficacy and little or no impact on male to female transmission, if there is disinhibition you may get an increased infection rate,” he said.
However Professor Robert Bailey of University of Illinois, Chicago, School of Public Health, speaking during a plenary session at the conference, pointed out that in the Kisumu study of medical circumcision, risk behaviours by circumcised men fell during the 12 months following circumcision.
He also noted that general circumcision programmes in countries outside Africa with low HIV prevalence (< 2%) are unlikely to prove cost-effective and may avert few HIV infections. Instead more targeted programmes to high-risk heterosexual men should be explored.
Circumcision services should be made available as soon possible in high prevalence settings, he said, highlighting a modelling study looking at the effect of differing paces of circumcision scale-up in South Africa.
“If we delay, at the end of 8 years we will have averted 16.4% fewer HIV infections and the cost per infection averted will be greater. Not delaying in putting our best efforts to providing services now will save lives and save money.”