Benefits of including males living with HIV in voluntary medical male circumcision - modelling analysis

Could circumcision of HIV-positive males benefit voluntary medical male circumcision programs in Africa? Mathematical modeling analysis.

Awad SF, Sgaier SK, Lau FK, Mohamoud YA, Tambatamba BC, Kripke KE, Thomas AG, Bock N, Reed JB, Njeuhmeli E, Abu-Raddad LJ. PLoS One. 2017 Jan 24;12(1):e0170641. doi: 10.1371/journal.pone.0170641. eCollection 2017.

Background: The epidemiological and programmatic implications of inclusivity of HIV-positive males in voluntary medical male circumcision (VMMC) programs are uncertain. We modeled these implications using Zambia as an illustrative example.

Methods and findings: We used the Age-Structured Mathematical (ASM) model to evaluate, over an intermediate horizon (2010-2025), the effectiveness (number of VMMCs needed to avert one HIV infection) of VMMC scale-up scenarios with varying proportions of HIV-positive males. The model was calibrated by fitting to HIV prevalence time trend data from 1990 to 2014. We assumed that inclusivity of HIV positive males may benefit VMMC programs by increasing VMMC uptake among higher risk males, or by circumcision reducing HIV male-to-female transmission risk. All analyses were generated assuming no further antiretroviral therapy (ART) scale-up. The number of VMMCs needed to avert one HIV infection was projected to increase from 12.2 VMMCs per HIV infection averted, in a program that circumcises only HIV-negative males, to 14.0, in a program that includes HIV-positive males. The proportion of HIV-positive males was based on their representation in the population (e.g. 12.6% of those circumcised in 2010 would be HIV-positive based on HIV prevalence among males of 12.6% in 2010). However, if a program that only reaches out to HIV-negative males is associated with 20% lower uptake among higher-risk males, the effectiveness would be 13.2 VMMCs per infection averted. If improved inclusivity of HIV-positive males is associated with 20% higher uptake among higher-risk males, the effectiveness would be 12.4. As the assumed VMMC efficacy against male-to-female HIV transmission was increased from 0% to 20% and 46%, the effectiveness of circumcising regardless of HIV status improved from 14.0 to 11.5 and 9.1, respectively. The reduction in the HIV incidence rate among females increased accordingly, from 24.7% to 34.8% and 50.4%, respectively.

Conclusion: Improving inclusivity of males in VMMC programs regardless of HIV status increases VMMC effectiveness, if there is moderate increase in VMMC uptake among higher-risk males and/or if there is moderate efficacy for VMMC against male-to-female transmission. In these circumstances, VMMC programs can reduce the HIV incidence rate in males by nearly as much as expected by some ART programs, and additionally, females can benefit from the intervention nearly as much as males.

Abstract [1]  Full-text [free] access [2] [1]

Editor’s notes: Evidence from randomised control trials and modelling studies suggest that voluntary male medical circumcision (VMMC) is a cost-effective HIV prevention programme. A deterministic compartmental age structured HIV model was used to assess benefits of including HIV positive males in VMMC programmes. The HIV model was parameterized using HIV biological and behavioural data for sub-Saharan Africa.  The model was fit to HIV prevalence for Zambia in the years between 1990 and 2014. The model used baseline circumcision coverages from Zambia Demographic and Health Survey 2007. The authors analysed the model for three VMMC programme scenarios; circumcising HIV negative males only, circumcising both HIV negative and HIV positive males, and circumcising males regardless of their HIV status. Sensitivity analysis was conducted to ascertain the robustness of key model assumptions on the study findings. The findings from the study suggest that, improving the inclusivity of all males is likely to improve the effectiveness of VMMC programmes.  This will be the case if there is moderate increase in uptake among higher-risk males and/or moderate VMMC efficacy in preventing male-to-female transmission. This is a very interesting modelling study which gives insights to policymakers on factors to consider in designing VMMC programmes. 

Africa [8]
Zambia [9]
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