Risk of incident tuberculosis after severe COVID-19: a nationwide cohort study

Severe viral infections can disrupt host immunity and increase susceptibility to secondary pathogens. Experimental and preclinical studies suggest that severe viral pneumonia may also trigger reactivation of Mycobacterium tuberculosis infection, yet population-level evidence remains limited. We conducted a nationwide retrospective cohort study in Chile, including more than 3.6 million adults with confirmed SARS-CoV-2 infection, to assess the risk of incident tuberculosis during follow-up. Individuals who developed severe COVID-19 requiring hospitalization had more than an eightfold higher hazard of tuberculosis within one year compared with those with non-severe disease. SARS-CoV-2 vaccination modified this association: the excess risk was substantially greater among unvaccinated individuals, whereas prior vaccination attenuated it. These findings indicate that severe COVID-19 is associated with an increased short- and long-term risk of tuberculosis and support the integration of targeted tuberculosis screening and preventive strategies into post-COVID-19 care, particularly among patients with severe disease.