Impact of repeated population-wide active TB screening and decentralized molecular diagnostics on TB burden in Lakshadweep, India.

BACKGROUND: The Union Territory (UT) of Lakshadweep, comprising approximately 70,000 inhabitants across ten inhabited islands in the Arabian Sea, faces logistical challenges that have historically impeded timely tuberculosis (TB) diagnosis and treatment. To accelerate progress towards TB elimination, repeated population-wide active TB screening and decentralized molecular diagnostic services were implemented between 2017 and 2024. OBJECTIVE: To describe changes in incident bacteriologically confirmed pulmonary TB notification rates following implementation of repeated population-wide active TB screening and decentralized molecular diagnostics in Lakshadweep. METHODS: Population-wide active TB screening campaigns were conducted across all inhabited islands in 2017, 2018, and annually from 2020 to 2024. Accredited Social Health Activists conducted door-to-door screening using a standardized four-symptom tool. Rapid molecular diagnostic facilities (NAAT) were established in six major islands in 2019 and expanded to the remaining inhabited islands by 2020. Chest radiography was offered to household contacts from 2020 and expanded to clinically vulnerable individuals from 2022. Trends in incident bacteriologically confirmed pulmonary TB notification rates were analyzed using routine programme data. RESULTS: Population coverage ranged from 68% to 84% across seven screening rounds, resulting in approximately 362,600 screening encounters. A total of 9402 individuals were identified as having presumptive TB and underwent diagnostic evaluation. Active screening detected 43 incident bacteriologically confirmed pulmonary TB cases, representing 34.1% of all 126 incident bacteriologically confirmed pulmonary TB cases notified between 2017 and 2024. More than 90% of diagnosed individuals were initiated on treatment, and treatment success exceeded 90% annually. The incident bacteriologically confirmed pulmonary TB notification rate declined from 39.0 per 100,000 population in 2015 to 10.0 per 100,000 population in 2024, a 74% reduction. CONCLUSION: Repeated population-wide active TB screening, supported by decentralized molecular diagnostics, was associated with a marked reduction in TB burden in Lakshadweep. Sustained high-coverage screening may accelerate progress toward TB elimination in settings with stable populations and well-defined geographic boundaries.