Tuberculosis Incidence and COVID-19 Related Mortality Rates in 20 Countries: An ecological study

Background: On 31 st December 2019, the China Country Office of the World Health Organization (WHO) reported cases of pneumonia of unknown etiology in the city of Wuhan in the province of Hubei. On 7 th January, 2020, the agent was described as a novel coronavirus (SARS-CoV-2) not previously detected in humans. Objectives: The aim of this study was to investigate the difference in the severity of the disease among various countries, in terms of the mechanism caused by SARS-CoV-2 in cellular immunity. Method: Countries with the highest numbers of coronavirus disease 2019 (COVID-19) cases as of July 2020 according to WHO data (USA, Brazil, India, Russia, the United Kingdom, Peru, Chile, Spain, Mexico, Iran, Pakistan, Italy, South Africa, Saudi Arabia, Turkey, Germany, France, Bangladesh, Colombia, and Canada) were included in the study. The average incidence of tuberculosis (TB) in the previous five years in these countries were then correlated with COVID-19-related mortality rates. Results: Correlation analysis revealed a negative, moderate relationship between COVID-19-related mortality and TB rates in the general population and in individuals over the age of 65 (r=-0.466, p=0.038 and r=-0.521, p=0.018, respectively). Conclusions: COVID-19-related mortality rates were low in those countries in which the incidence of TB was high, thus highlighting the importance of investigating the immunology of the virus in determining the severity of the disease.