Long-term effects of mass screening for latent and active tuberculosis in the Marshall Islands

Abstract Rationale The Marshall Islands implemented ambitious population-based screening programs for latent and active tuberculosis in 2017 and 2018. These interventions’ long-term effects remain to be estimated. Objectives To predict the long-term impact of the previous interventions and identify strategies to drive tuberculosis towards elimination. Methods We built a transmission model of tuberculosis informed by local data to capture the epidemic’s historical dynamics. We used the model to project the future epidemic trajectory following the screening interventions, as well as considering a counterfactual scenario with no intervention. We also simulated future scenarios including periodic interventions similar to those previously implemented, to assess the feasibility of reaching the End TB Strategy targets and tuberculosis pre-elimination. Measurements and Main Results The 2017-2018 screening activities were estimated to have reduced tuberculosis incidence and mortality by more than one third in 2020, and are predicted to achieve the End TB Strategy milestone of 50% incidence reduction by 2025 compared to 2015. Interventions had a considerably greater impact when individuals were also screened for latent infection than active case finding alone. Such combined programs implemented at the national level could achieve tuberculosis pre-elimination by 2035 if repeated every two years, and around 2045 if repeated every five years. Conclusions We predict that it is possible to achieve tuberculosis pre-elimination by 2035 in the Marshall Islands through periodic repetition of the same ambitious interventions as those previously implemented. Including latent infection testing in active screening activities will be a critical pillar for achieving these ambitious goals.