Browsing by Author "Vargas García, Salvador"

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    Reducing household tuberculosis transmission. A pilot cluster-randomized controlled trial
    (2025) Ruiz-Tagle Seguel, Cinthya Grace; Seguel Araus, Romina Javiera; Villarroel del Pino, Luis A.; Bernales, Margarita; Vargas García, Salvador; Pizarro Ibañez, Alejandra Valentina; Peña, Carlos; Neira, Víctor; García Cañete, Patricia; Allel Henríquez, Kasim Ignacio; Nathavitharana, Ruvandhi R.; Balcells Marty, María Elvira
    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.
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    Short- and long-term increased risk of all-cause mortality in a tuberculosis cohort attributed to SARS-CoV-2 infection: a time-dependent survival analysis in Chile
    (2025) Vargas García, Salvador; Undurraga, Eduardo A.; Escobar, Nadia; García, Christian; Vergara, Natalia; Balcells Marty, María Elvira
    Background: Concurrent tuberculosis (TB) and COVID-19 increases the risk of mortality; however, most studies have focused primarily on short-term outcomes. We assessed the short and long-term impact of TB and SARS-CoV-2 coinfection on all-cause mortality. Methods: We conducted a retrospective nationwide cohort study in Chile, including adults diagnosed with active TB from January 1st, 2020, to December 31st, 2021, with follow-up until November 30th, 2022. SARS-CoV-2 coinfection was defined as occurring from 30 days before to six months after TB diagnosis. Short-term mortality was defined as death within 90 days of TB or TB/SARS-CoV-2 diagnosis, and long-term mortality as death occurring after 90 days. We used a time-dependent Cox survival analysis, adjusting for sociodemographic factors, SARS-CoV-2 vaccination, and relevant comorbidities including HIV, diabetes and Mycobacterium tuberculosis drug-resistance status. Findings: The cohort included 3721 adults (median age: 47 years, interquartile range [IQR]: 32–61); of whom 63·4% were male, and 79·4% had pulmonary TB. The median follow-up was 586 days (IQR: 401–820), with 680 deaths (18·3%) recorded. A SARS-CoV-2 coinfection was identified in 393 individuals (10·5%); the mortality in this group was higher in short-term (≤90 days: 14·5% vs. 11·4%) and long-term (>90 days: 11·5% vs. 5·9%) compared to TB alone. Coinfection increased the risk of all-cause mortality during the entire follow-up (aHR [adjusted Hazard Ratio]: 2·8, 95% CI: 2·26–3·47), over three-fold in the short-term (aHR 3·4, 95% CI: 2·57–4·51) and nearly two-fold in the long-term (aHR: 1·72, 95% CI: 1·18–2·52). Excess mortality persisted beyond the first year (aHR: 2·04, 95% CI: 1·09–3·82). SARS-CoV-2 vaccination reduced mortality risk in the TB cohort by 35% (95% CI: 19–46%). Interpretation: Tuberculosis and SARS-CoV-2 coinfection was associated with significantly increased all-cause mortality in both the short and long-term, with elevated risk persisting beyond TB treatment completion. These findings highlight the need for continued post-treatment follow-up and prioritization of SARS-CoV-2 vaccination among individuals with TB.