Expanded voluntary counselling and testing services in Türkiye: insights from an HIV model

Voluntary Counselling and Testing (VCT) centres provide free and anonymous Human Immunodeficiency Virus (HIV) testing along with counselling services. They remove barriers to testing and lead to higher HIV awareness. The current healthcare system in Türkiye achieves high treatment rates in the continuum of care. However, the estimated diagnosis rates are far below the global targets, posing a significant challenge. This also creates an opportunity to intensify prevention efforts against the burden of the disease. Expanded VCT services is a suggested strategy for Türkiye, but research evaluating its effectiveness is lacking. We developed a dynamic compartmental model with different testing sites as separate compartments, distinguishing VCT centres from others. Using the data from each VCT centre, we quantified the impact of this strategy through various scenarios. We found that under the assumption that the VCT strategy primarily serves high-risk populations, it could yield 50 to 74-fold more pay-off in terms of the number of cases prevented per additional test than other facilities. A two- and four-fold increase in both types of testing facilities (VCT and other) would reduce annual incidence in 2033 by 71% and 91%, respectively, while prevalence was estimated to be 34% and 51% lower compared to no action. Our findings suggest that prioritizing VCT expansion is highly efficient strategy compared to other testing sites. Future research could focus on resource allocation, costs and benefits of the programs to ensure the optimal allocation of the resources to the most cost-effective public health strategies.