The Return on Investment of Scaling Tuberculosis Screening and Preventive Treatment: A Modelling Study in Brazil, Georgia, Kenya, and South Africa

Background Closing the tuberculosis diagnostic gap and scaling-up tuberculosis preventive treatment (TPT) are two major global priorities to end the tuberculosis epidemic. To help support these efforts, we modeled the impact and return-on-investment (ROI) of a comprehensive intervention to improve tuberculosis screening and prevention in Brazil, Georgia, Kenya, and South Africa—four distinct epidemiological settings. Methods We worked with national tuberculosis programmes (NTP) in each country to define a set of interventions (“the intervention package”) related to tuberculosis screening and TPT in three priority populations: people with HIV, household contacts, and a country-defined high-risk population. We developed transmission models calibrated to tuberculosis epidemiology for each country, and collated cost data related to tuberculosis-related activities and patient costs in 2023 $USD. We compared the intervention package without and with TPT scaled-up to reach priority populations to a status quo scenario based on projected tuberculosis epidemiology over a 27-year time horizon (2024-2050). Outcomes were health system and societal costs, number of tuberculosis episodes, tuberculosis deaths, and disability adjusted life years (DALYs). We performed 1000 simulations and calculated the mean and 95% uncertainty range (95%UR) difference in outcomes between the intervention package and the status quo. We calculated the health system cost per DALY averted and societal return on the health system investment for each country. We did not discount costs or outcomes in the base scenario. Findings Under the status quo, by 2050, tuberculosis incidence is projected to be 39 (95%UR 37-43), 34 (24-50), 204 (186-255), and 208 (124-293) per 100,000 population in Brazil, Georgia, Kenya, and South Africa, respectively. Implementing the intervention package without TPT is projected to reduce tuberculosis incidence by 9.6% (95%UR 9.3-10), 14.4% (11-19.6), 30.3% (29-33.1), and 22.7% (19.4-27.2) in Brazil, Georgia, Kenya, and South Africa, respectively, by 2050. The addition of TPT is projected to further reduce tuberculosis incidence by 9.5% (95%UR 9.3-9.8), 10.9% (9.8-12.3), 19.2% (17.6-20.1), and 13.1% (11.2-14.4%). From the health system perspective, the incremental cost per DALY averted of the intervention package is $771 in Brazil, $1402 in Georgia, $521 in Kenya, and $163 in South Africa. The societal return per $1 invested by the health system is projected to be $10.80, $3.70, $27.40, and $39.00 in Brazil, Georgia, Kenya, and South Africa, respectively. Interpretation Scaling-up interventions related to tuberculosis screening and TPT in priority populations is projected to substantially reduce tuberculosis incidence and provide large returns on investment. Funding World Health Organization. ### Competing Interest Statement SDB, DF, IGB, NA, and CM are staff members of the World Health Organization. The authors alone are responsible for the views expressed in this article and they do not necessarily represent the views, decisions or policies of the World Health Organization or other institutions with which they are affiliated. ### Funding Statement This study was funded by the World Health Organization Global TB Programme. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data is available from the authors upon request. All code in support of TB transmission models can be found in the following online repository