Deering Kathleen N, Vickerman Peter, Moses Stephen, Ramesh Banadakoppa M, Blanchard James F, Boily Marie-Claude
School of Population and Public Health, University of British Columbia, Vancouver, Canada.
AIDS. 2008 Dec;22 Suppl 5:S165-81. doi: 10.1097/01.aids.0000343774.59776.95.
Seasonal migration may be an important driver of the HIV epidemic in India; however, migrant sexual behaviour data are limited. This study assessed the extent to which migration could explain heterogeneity in HIV prevalence in Bagalkot district, in Karnataka state, India, examining important migration-related risk factors for HIV transmission and implications for prevention.
We used mathematical modelling to explore the potential impact of different seasonal migration patterns on HIV prevalence.
A deterministic compartmental mathematical model of heterosexually transmitted HIV infection was developed. Six migration scenarios were explored, depending on which population migrated (men/clients only/female sex workers; FSW), and which local population determined the demand for commercial sex while migrants were away.
The impact of migration varied substantially across the six migration scenarios. Migration was unlikely to explain heterogeneity in HIV prevalence unless a fraction of all men migrated and local FSW drove the demand for commercial sex. Even with very high-risk migrant sexual behaviour in the migration destination, targeting interventions at 30%-100% of local core groups could prevent a maximum of 12%-40% of new infections (87% effective condoms), from 2004-2015. Targeting migrants locally and at their destination could have up to 1.6-times the impact of targeting migrants only at their destination.
Results suggest that core group interventions introduced locally because of the difficulty of reaching migrant populations could still be beneficial. Understanding how local sexual networks change during migration is crucial for understanding the impact of migration on HIV transmission, and for designing HIV preventive interventions.
季节性迁移可能是印度艾滋病流行的一个重要驱动因素；然而，关于迁移人群性行为的数据有限。本研究评估了迁移在多大程度上可以解释印度卡纳塔克邦巴加尔科特地区艾滋病病毒感染率的异质性，研究了与迁移相关的重要艾滋病病毒传播风险因素及其对预防工作的影响。
我们使用数学模型来探索不同季节性迁移模式对艾滋病病毒感染率的潜在影响。
建立了一个异性传播艾滋病病毒感染的确定性 compartmental 数学模型。根据迁移的人群（仅男性/客户/女性性工作者；FSW）以及在迁移者外出期间当地哪些人群决定对商业性服务的需求，探索了六种迁移情景。
在六种迁移情景中，迁移的影响差异很大。除非所有男性中有一部分迁移且当地女性性工作者推动对商业性服务的需求，否则迁移不太可能解释艾滋病病毒感染率的异质性。即使在迁移目的地存在非常高风险的迁移人群性行为，针对当地核心人群的 30% - 100%进行干预，在 2004 - 2015 年期间最多可预防 12% - 40%的新感染（避孕套有效率为 87%）。在当地和迁移目的地针对迁移人群进行干预的效果可能是仅在迁移目的地针对迁移人群进行干预效果的 1.6 倍。
结果表明，由于难以接触到迁移人群而在当地开展的核心人群干预措施仍可能有益。了解迁移期间当地性网络如何变化对于理解迁移对艾滋病病毒传播的影响以及设计艾滋病病毒预防干预措施至关重要。
