Background:
Three randomised controlled trials have clearly shown that circumcision of adult men reduces the chance that
they acquire HIV infection. However, the potential impact of circumcision programmes – either alone or in combination
with other established approaches – is not known and no further field trials are planned. We have used a mathematical
model, parameterised using existing trial findings, to understand and predict the impact of circumcision programmes at the
population level.
Findings:
Our results indicate that circumcision will lead to reductions in incidence for women and uncircumcised men, as
well as those circumcised, but that even the most effective intervention is unlikely to completely stem the spread of the
virus. Without additional interventions, HIV incidence could eventually be reduced by 25–35%, depending on the level of
coverage achieved and whether onward transmission from circumcised men is also reduced. However, circumcision
interventions can act synergistically with other types of prevention programmes, and if efforts to change behaviour are
increased in parallel with the scale-up of circumcision services, then dramatic reductions in HIV incidence could be achieved.
In the long-term, this could lead to reduced AIDS deaths and less need for anti-retroviral therapy. Any increases in risk
behaviours following circumcision , i.e. ‘risk compensation’, could offset some of the potential benefit of the intervention,
especially for women, but only very large increases would lead to more infections overall.
Conclusions:
Circumcision will not be the silver bullet to prevent HIV transmission, but interventions could help to
substantially protect men and women from infection, especially in combination with other approaches.