Reducing Household Tuberculosis Transmission: A Pilot Cluster-Randomized Controlled Trial.

BACKGROUND: The duration of infectiousness following pulmonary tuberculosis treatment initiation remains uncertain. We aimed to assess whether a bundled intervention designed to decrease respiratory exposure was feasible and would reduce new tuberculosis infections in household contacts (HHCs). METHODS: We conducted a pilot cluster-randomized controlled trial with a hybrid type 1 effectiveness-implementation design in Santiago, Chile. Random allocation was performed, and two healthcare districts were assigned to the intervention (n=180 HHCs) and one to standard of care (n=149 HHCs). Eligible participants were newly diagnosed pulmonary tuberculosis patients and their HHCs. The intervention included education, mask use, household ventilation, and nightly separation of tuberculosis patients, for two weeks. Intervention adherence was evaluated weekly. Effectiveness was assessed at the individual level with QuantiFERON®-TB Gold Plus (QFT) test conversions in HHCs at 12-week follow-up. RESULTS: Between October 2021 and December 2023, 384 HHCs and 157 tuberculosis patients were enrolled. Overall, 56.3% of contacts were women, with mean age of 34.6 years and a baseline QFT positivity of 32.3%. A total of 216 contacts had negative QFT result at baseline, with 179 (82.9%) completing follow-up. QFT conversions occurred in 11 (12.8%) and 10 (10.8%) HHCs from the intervention and control arms, respectively (incidence risk ratio 1.10, 95% CI 0.71-1.71, p=0.849). Good adherence to the respiratory bundle was reported by 53% of participants on day 7 and 54% on day 14. CONCLUSIONS: Isolation and restrictive measures after tuberculosis treatment initiation resulted challenging, and did not reduce tuberculosis infections in HHCs, suggesting limited benefit for transmission control.