Lower Incidences and Deaths Due to COVID-19 in Countries with high Deaths Due to Tuberculosis and Flu: a 2021-2022 Update

Heterogeneity in number of deaths in various countries due to COVID-19 is likely due to multiple factors. Previously, our laboratory has shown, using 2020 epidemiological data, that countries with high deaths due to tuberculosis and flu display less COVID-19 deaths. Also, countries with high BCG but low flu vaccinations display less COVID-19 deaths. It was important to address whether this trend held as the pandemic progressed in 2021-2022 given the rise of SARS-CoV2 variants and COVID-19 vaccinations. In this study, countries with more than 10,000 COVID-19 deaths were selected at four time points and the data was analysed. COVID-19 incidences/million and deaths/million were obtained from various data bases and correlation analysis was performed with tuberculosis deaths, flu deaths, BCG and flu vaccination coverages. The main findings are: First, countries with high tuberculosis deaths show negative correlation with COVID-19 incidences and deaths. This pattern is also true for countries with high BCG vaccinations. Second, countries with high flu deaths display less COVID-19 incidences and deaths. Concomitantly, countries with high flu vaccinations show higher COVID-19 incidences and deaths. Third, countries with high deaths due to tuberculosis and flu display lower COVID-19 incidences and deaths. Finally, countries with high BCG coverage and tuberculosis deaths (e.g. Bangladesh, India, Indonesia, etc) display lower COVID-19 incidences and deaths, compared to countries with high BCG coverage but low tuberculosis deaths (e.g. Brazil, Mexico, Russia etc), demonstrating roles for both. This global study reveals a complex interplay of the roles of other respiratory pathogens in limiting COVID-19.