Modelling the health and cost implications of expanded access to HIV, HCV and sexually transmitted infection testing in Switzerland

Unlabelled:   BACKGROUND: This study was conducted as part of the Swiss National Programme to Stop HIV, Hepatitis B Virus, Hepatitis C Virus and Sexually Transmitted Infections (NAPS), which aims to reduce the spread of sexually transmitted infections in Switzerland. The goal was to identify the most effective and cost-efficient screening strategies to lower the incidence of human immunodeficiency virus (HIV), hepatitis C virus (HCV), syphilis, Neisseria gonorrhoeae and Chlamydia trachomatis by improving access to screening. Methods: A Markov model was developed to assess the impact of various screening strategies among key populations over two years, including men who have sex with men (MSM), female sex workers (FSW) and people who inject drugs (PWID). The model further stratifies individuals based on partner number (MSM) and injection-equipment sharing (PWID). Comprehensive cost estimates for screening and treatment were derived from insurance data, literature and expert opinions. The effectiveness of screening interventions was evaluated by measuring reductions in disease incidence and cost savings, comparing the costs of screening to those of acute and chronic care for prevented infections. Results: Increased screening frequency among key populations led to a reduction in incidence for all five infections studied. The largest effect was seen in people who inject drugs who share injecting equipment, where HCV incidence fell by up to 76% with four annual screens. However, only screening for HIV, HCV and syphilis proved to be cost-saving. Screening for Chlamydia trachomatis and Neisseria gonorrhoeae consistently incurred net costs due to the high screening costs and relatively low treatment costs. Conclusion: Targeted expansion of screening among key populations can reduce the incidence of HIV, HCV and syphilis in Switzerland, with regular screening offering potential cost savings to insurers under specific coverage and treatment scenarios.