Scandrett, KatiePallett, ScottTakwoingi, YemisiCunningham, Adam FDedicoat, MartinO'Shea, Matthew K2025-11-112025-11-112025-10-13Scandrett K, Pallett S, Takwoingi Y, Cunningham AF, Dedicoat M, O'Shea MK. Previously treated latent tuberculosis infection is associated with less severe acute COVID-19: a cohort study. BMJ Open Respir Res. 2025 Oct 13;12(1):e003003. doi: 10.1136/bmjresp-2024-003003.2052-443910.1136/bmjresp-2024-0030034108327712/1/e003003https://westmid.openrepository.com/handle/20.500.14200/9040Introduction There is significant potential for respiratory infections, such as tuberculosis (TB) and COVID-19, to overlap but little is known about such co-infection. We aimed to study the impact of active TB and latent TB on the incidence of severe COVID-19 in a large cohort of individuals in a setting of low TB endemicity. Methods Clinical data of patients admitted to hospital with acute SARS-CoV-2 were merged with a database of patients with a history of previous or current active TB, latent TB or healthy controls. We assessed the incidence of COVID-19 in these groups, length of hospital stay, admission to the intensive care unit (ICU) and in-hospital mortality. Results COVID-19 incidence among individuals with current active TB was 6.2% (12/194) and previous active TB 0.67% (30/4496). In contrast, the incidence in previously treated latent TB was 0.09% (4/4542) and among TB contacts 0.24% (34/13 391). There were similar rates of ICU admission and mortality among individuals with COVID-19 and current active TB, TB contacts and other patients. No individuals with previously treated latent TB and COVID-19 were admitted to the ICU or died. Conclusions Individuals with a history of latent TB seem to be at reduced risk of severe COVID-19 and have better outcomes than those with active TB and even uninfected controls. Further studies are required to understand the mechanistic basis of this observation.en© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY. Published by BMJ Group.TuberculosisViral diseasesJournal Article