Chest Computed Tomography (CT) Severity Score Assessment to Explore Association between Tuberculosis and COVID-19 Pneumonia for Assessing the TB Bulwark against Moderate to Severe COVID-19 Infection.

Sharma, Rajaram; Lodha, Sambhav; Mehta, Ritu; Chugh, Sunil; Mathur, Girish

Importance Objective: First case of Covid-19 pneumonia was reported in Wuhan and soon it became pandemic.1 Pulmonary tuberculosis (TB) is mainly a disease of tropical and poor countries like India.9 Initially, it wasn't clear how these two diseases will interact with each other. We tried to determine if TB has any impact on course and prognosis of Covid-19 pneumonia. DESIGN SETTING In this retrospective analytical study, data of 7774 patients were collected from various state government owned hospitals of India. Chest CT scans were reviewed for present or past stigmata of pulmonary TB, CORADS and CT severity score. Statistical analysis was done for class wise frequency distribution and association of attributes were calculated. RESULTS 95.01% Patients with Covid-19 pneumonia didn't have CT signs of history of active or old healed pulmonary TB, while 4.99% had it. In first group 44.85 % mild, 36.17 % moderate and 13.98 % had severe disease, while in second group figure is 3.39 % 1.21 % and 0.40 % respectively. Probability of TB providing immunity against developing moderate or severe form of Covid-19 pneumonia is 0.6778. CONCLUSIONS Patients with active or past history of TB are less prone to develop moderate or severe form of Covid-19 pneumonia. It may be the reason for less mortality in health resource poor India as compared to Europe or America.