Cost and cost-effectiveness analysis of near point-of-care GeneXpert testing for STIs in South Africa: leveraging current capacity to address high prevalence of Chlamydia trachomatis, Neisseria gonorrhoeae and Trichomonas vaginalis

BackgroundSouth Africa has high sexually transmitted infections (STIs) prevalence and currently implement syndromic management, which has limitations such as untreated asymptomatic infections and antibiotic misuse. Diagnostic tools, like GeneXpert may offer potential improvements. We evaluated costs, cost-effectiveness and budget impact of reallocating GeneXpert capacity for STIs testing. MethodsWe developed static analytical model using previously collected data. Over one-year time horizon from provider perspective, we compared costs reported in 2024 USD and outcomes of syndromic management and nine scenarios using near point-of-care GeneXpert testing for Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis in various target groups, including symptomatic individuals, antenatal care (ANC) attendees and HIV testers (Adolescent girls and young women (AGWY), and adults). Univariate sensitivity analysis was conducted to assess uncertainty of key parameters. ResultsCost per person treated and correctly treated ranged from $21-$29 (syndromic management) and $88-$579 in GeneXpert scenarios. Syndromic management cost the healthcare system an estimated $24 million, GeneXpert testing would cost substantially more: $207 million (symptomatic), $116 million (ANC attendees), $1.7 billion (HIV testers), and $310-$884 million for targeted/combined approaches involving ANC attendees, AGWY and symptomatic individuals, and increase number of cases correctly treated by over 3-fold. Of scenarios modelled, two were cost-effective: 1) AGYW HIV testers and adults with STI symptoms, and 2) adults (15-49 years) having either HIV test or STI symptoms, incremental cost per additional case correctly treated was $515 and $1,079, respectively. While they are cost-effective, they would cost $2.26 and $10.52 billion over 5-years, respectively, compared to $145 million in syndromic management. Cost of cartridge was most influential parameter in sensitivity analysis. ConclusionsPrioritizing symptomatic individuals, high-risk groups (i.e HIV testers), and cost-effective interventions can improve cases correctly treated but requires additional budget. These findings support the need for targeted strategies to optimise clinical and economic benefits of GeneXpert testing for STIs.