Monday, July 16, 2007

The impact of male circumcision on HIV incidenc

The impact of male circumcision on HIV incidence and cost per infection prevented: a stochastic simulation model from Rakai, Uganda.

AIDS. 2007 Apr 23;21(7):845-50.
Gray RH, Li X, Kigozi G, Serwadda D, Nalugoda F, Watya S, Reynolds SJ, Wawer M.

OBJECTIVES: To estimate the impact of male circumcision on HIV incidence, the number of procedures per HIV infection averted, and costs per infection averted.

METHODS: A stochastic simulation model with empirically derived parameters from a cohort in Rakai, Uganda was used to estimate HIV incidence, assuming that male circumcision reduced the risks of HIV acquisition with rate ratios (RR) ranging from 0.3 to 0.6 in men, their female partners, and in both sexes combined, with circumcision coverage 0-100%. The reproductive number (R0) was also estimated. The number of HIV infections averted per circumcision was estimated from the incident cases in the absence of surgery minus the projected number of incident cases over 10 years following circumcision. The cost per procedure ($69.00) was used to estimate the cost per HIV infection averted.

RESULTS: Baseline HIV incidence was 1.2/100 person-years. Male circumcision could markedly reduce HIV incidence in this population, particularly if there was preventative efficacy in both sexes. Under many scenarios, with RR < or = 0.5, circumcision could reduce R0 to < 1.0 and potentially abort the epidemic. The number of surgeries per infection averted over 10 years was 19-58, and the costs per infection averted was $1269-3911, depending on the efficacy of circumcision for either or both sexes, assuming 75% service coverage. However, behavioral disinhibition could offset any benefits of circumcision.

CONCLUSION: Male circumcision could have substantial impact on the HIV epidemic and provide a cost-effective prevention strategy if benefits are not countered by behavioral disinhibition.


The issue of behavioural disinhibition has been found in the following study to be unlikely to be an area of concern.


J Acquir Immune Defic Syndr. 2007 Jan 1;44(1):66-70.

Male circumcision in Siaya and Bondo Districts, Kenya: prospective cohort study to assess behavioral disinhibition following circumcision.

Agot KE, Kiarie JN, Nguyen HQ, Odhiambo JO, Onyango TM, Weiss NS.

BACKGROUND: Evidence for efficacy of male circumcision as an HIV prevention measure is increasing, but there is serious concern that men who are circumcised may subsequently adopt more risky sexual behaviors.

METHODS: Using a prospective cohort study, we compared sexual behaviors of 324 recently circumcised and 324 uncircumcised men at 1, 3, 6, 9, and 12 months after circumcision/study enrollment. The main outcome indicators were incidence of sexual behaviors known to place men at increased risk of acquiring HIV, namely, having sex with partners other than their wife/wives for married men or other than "regular" girlfriends for unmarried men.

RESULTS: During the first month following circumcision, men were 63% and 61% less likely to report having 0 to 0.5 and >0.5 risky sex acts/week, respectively, than men who remained uncircumcised. This difference disappeared during the remainder of follow-up, with no excess of reported risky sex acts among circumcised men. Similar results were observed for risky unprotected sex acts, number of risky sex partners, and condom use.

DISCUSSION: During the first year post-circumcision, men did not engage in more risky sexual behaviors than uncircumcised men, suggesting that any protective effect of male circumcision on HIV acquisition is unlikely to be offset by an adverse behavioral impact.