Active or latent tuberculosis increases susceptibility to COVID-19 and disease severity

Importance: Risk factors associated with COVID-19, the viral pneumonia originating in Wuhan, China, in Dec 2019, require clarification so that medical resources can be prioritized for those at highest risk of severe COVID-19 complications. Infection with M. tuberculosis (MTB), the pathogen that causes TB and latently infects ~25% of the global population, may be a risk factor for SARS-CoV-2 infection and severe COVID-19 pneumonia. Objective: To determine if latent or active TB increase susceptibility to SARS-COV-19 infection and disease severity, and lead to more rapid development of COVID-19 pneumonia. Design: An observational case-control study of 36 confirmed COVID-19 cases from Shenyang, China, conducted in Feb 2020. Final date of follow-up: Feb 29, 2020. Cases were grouped according to COVID-19 pneumonia severity (mild/moderate, severe/critical), and MTB infection status compared. Comparisons were made with MTB infection data from another case-control study on bacterial/viral pneumonia at Shenyang Chest Hospital. Setting: Multi-center study involving three primary care hospitals in Shenyang, China. Participants: 86 suspected COVID-19 cases from participating primary-care hospitals in Shenyang. All 36 SARS-CoV-2 +ve cases (based on RT-PCR assay) were included. Disease severity was assessed using the Diagnostic and Treatment Guidelines of the National Health Commission of China (v6). Mean age, 47 years (range: 25-79), gender ratio, 1:1. Exposures: Confirmed COVID-19 pneumonia. Interferon-gamma Release Assays (IGRA) were performed using peripheral blood to determine MTB infection. Main Outcome and Measures: Epidemiological, demographic, clinical, radiological, and laboratory data were collected. Comparison of MTB infection status between patients with mild/moderate and severe/critical COVID-19 pneumonia. Results: Mean age of 36 COVID-19 patients: 47 (range: 25-79); M/F: 18/18; Wuhan/Hubei connection: 42%. Mild/moderate cases: 27 (75%); severe/critical: 9 (25%). MTB infection (IGRA+ve): 13 cases (36.11%), including 7 of 9 severe/critical cases. MTB infection rate: higher in COVID-19 (36.11%) than bacterial pneumonia (20%; p=0.0047) and viral pneumonia patients (16.13%; p=0.024). MTB infection more common than other co-morbidities (36.11% vs diabetes: 25%; hypertension: 22.2%; coronary heart disease: 8.33%; COPD: 5.56%). MTB co-infection linked with disease severity (severe/critical 78% vs mild/moderate cases 22%; p=0.0049), and rate of disease progression: infection to development of symptoms (MTB+SARS-CoV-2: 6.5+/-4.2 days vs SARS-COV-2: 8.9+/-5.2 days; p=0.073); from symptom development to diagnosed as severe (MTB+SARS-CoV-2: 3.4+/-2.0 days vs SARS-COV-2: 7.5+/-0.5 days; p=0.075). Conclusions and Relevance: MTB infection likely increases susceptibility to SARS-CoV-2, and increases COVID-19 severity, but this requires validation in a larger study. MTB infection status of COVID-19 patients should be checked routinely at hospital admission.