Estimating the contribution of key populations towards HIV transmission in South Africa

INTRODUCTION: In generalized epidemic settings, there is insufficient understanding of how the unmet HIV prevention and treatment needs of key populations (KPs), such as female sex workers (FSWs) and men who have sex with men (MSM), contribute to HIV transmission. In such settings, it is typically assumed that HIV transmission is driven by the general population. We estimated the contribution of commercial sex, sex between men, and other heterosexual partnerships to HIV transmission in South Africa (SA). METHODS: We developed the "Key-Pop Model"; a dynamic transmission model of HIV among FSWs, their clients, MSM, and the broader population in SA. The model was parameterized and calibrated using demographic, behavioural and epidemiological data from national household surveys and KP surveys. We estimated the contribution of commercial sex, sex between men and sex among heterosexual partnerships of different sub-groups to HIV transmission over 2010 to 2019. We also estimated the efficiency (HIV infections averted per person-year of intervention) and prevented fraction (% IA) over 10-years from scaling-up ART (to 81% coverage) in different sub-populations from 2020. RESULTS: Sex between FSWs and their paying clients, and between clients with their non-paying partners contributed 6.9% (95% credibility interval 4.5% to 9.3%) and 41.9% (35.1% to 53.2%) of new HIV infections in SA over 2010 to 2019 respectively. Sex between low-risk groups contributed 59.7% (47.6% to 68.5%), sex between men contributed 5.3% (2.3% to 14.1%) and sex between MSM and their female partners contributed 3.7% (1.6% to 9.8%). Going forward, the largest population-level impact on HIV transmission can be achieved from scaling up ART to clients of FSWs (% IA = 18.2% (14.0% to 24.4%) or low-risk individuals (% IA = 20.6% (14.7 to 27.5) over 2020 to 2030), with ART scale-up among KPs being most efficient. CONCLUSIONS: Clients of FSWs play a fundamental role in HIV transmission in SA. Addressing the HIV prevention and treatment needs of KPs in generalized HIV epidemics is central to a comprehensive HIV response

Feasibility and cost effectiveness of interventions to prevent tuberculosis and HIV in South Africa

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Costs of measures to control tuberculosis/HIV in public primary care facilities in Cape Town, South Africa.

OBJECTIVE: To measure the costs and estimate the cost-effectiveness of the ProTEST package of tuberculosis/human immunodeficiency virus (TB/HIV) interventions in primary health care facilities in Cape Town, South Africa. METHODS: We collected annual cost data retrospectively using ingredients-based costing in three primary care facilities and estimated the cost per HIV infection averted and the cost per TB case prevented. FINDINGS: The range of costs per person for the ProTEST interventions in the three facilities were: US$7-11 for voluntary counselling and testing (VCT), US$ 81-166 for detecting a TB case, US$92-183 for completing isoniazid preventive therapy (IPT) and US$ 20-44 for completing six months of cotrimoxazole preventive therapy. The estimated cost per HIV infection averted by VCT was US$67-112. The cost per TB case prevented by VCT (through preventing HIV) was US$ 129-215, by intensified case finding was US$323-664 and by IPT was US$ 486-962. Sensitivity analysis showed that the use of chest X-rays for IPT screening decreases the cost-effectiveness of IPT in preventing TB cases by 36%. IPT screening with or without tuberculin purified protein derivative screening was almost equally cost-effective. CONCLUSION: We conclude that the ProTEST package is cost saving. Despite moderate adherence, linking prevention and care interventions for TB and HIV resulted in the estimated costs of preventing TB being less than previous estimates of costs of treating it. VCT was less expensive than previously reported in Africa