School of Social and Community Medicine, University of Bristol, Bristol, UK.
Division of Global Public Health, University of California San Diego, La Jolla, CA, UK.
Int J Epidemiol. 2017 Oct 1;46(5):1582-1592. doi: 10.1093/ije/dyx075.
Uncertainty surrounds why hepatitis C virus (HCV) is concentrated among HIV-positive men who have sex with men (MSM). We used mathematical modelling to explore reasons for these infection patterns, and implications for HCV treatment-as-prevention.
Using a joint MSM HIV/HCV transmission model parameterized with UK behavioural data, we considered how biological (heightened HCV infectivity and reduced spontaneous clearance among HIV-positive MSM) and/or behavioural factors (preferential sexual mixing by HIV status and risk heterogeneity) could concentrate HCV infection in HIV-positive MSM as commonly observed (5-20 times the HCV prevalence in HIV-negative MSM; defined as the HCV ratio). We explored how HCV treatment-as-prevention impact varies under differing HCV ratios.
Biological factors produced low HCV ratios (< 3), not explaining the skewed epidemic. However, combining preferential mixing by HIV status with sexual risk behaviour heterogeneity produced high HCV ratios (> 10) that were highly sensitive to both factors. Irrespective of the HCV ratio or behavioural/biological factors, HCV treatment of HIV-diagnosed MSM markedly reduced the HCV prevalence among HIV-positive MSM, but less impact was achieved among all MSM for lower HCV ratios.
Sexual behaviour patterns likely drive observed HCV infection patterns among HIV-positive MSM. Changes in these patterns could disseminate HCV amongst HIV-negative MSM, limiting the impact of targeting HCV treatment to HIV-diagnosed MSM.
丙型肝炎病毒 (HCV) 为何集中在与男性发生性关系的 HIV 阳性男性 (MSM) 中，原因尚不清楚。我们使用数学模型来探索这些感染模式的原因，以及对 HCV 治疗即预防的影响。
我们使用经过英国行为数据参数化的联合 MSM HIV/HCV 传播模型，考虑了生物因素（HIV 阳性 MSM 中 HCV 的感染力增强和自发清除减少）和/或行为因素（HIV 状态和风险异质性导致的偏好性性混合）如何将 HCV 感染集中在 HIV 阳性 MSM 中，就像通常观察到的那样（HIV 阴性 MSM 的 HCV 流行率的 5-20 倍；定义为 HCV 比值）。我们探讨了在不同 HCV 比值下 HCV 治疗即预防的影响变化。
生物因素产生的 HCV 比值较低（<3），无法解释偏态流行。然而，将 HIV 状态偏好性混合与性行为风险行为异质性相结合，产生了 HCV 比值较高（>10），对这两个因素都非常敏感。无论 HCV 比值或行为/生物因素如何，对 HIV 确诊 MSM 的 HCV 治疗都显著降低了 HIV 阳性 MSM 中的 HCV 流行率，但对于较低的 HCV 比值，对所有 MSM 的影响较小。
性行为模式可能是 HIV 阳性 MSM 中观察到的 HCV 感染模式的驱动因素。这些模式的变化可能会在 HIV 阴性 MSM 中传播 HCV，从而限制针对 HIV 确诊 MSM 的 HCV 治疗的影响。
