BCG vaccine protection from severe coronavirus disease 2019 (COVID-19)
Luis E. Escobar, Alvaro Molina-Cruz, Carolina Barillas‐Mury
Abstract
Significance The COVID-19 pandemic is one of the most devastating in recent history. The bacillus Calmette−Guérin (BCG) vaccine against tuberculosis also confers broad protection against other infectious diseases, and it has been proposed that it could reduce the severity of COVID-19. This epidemiological study assessed the global linkage between BCG vaccination and COVID-19 mortality. Signals of BCG vaccination effect on COVID-19 mortality are influenced by social, economic, and demographic differences between countries. After mitigating multiple confounding factors, several significant associations between BCG vaccination and reduced COVID-19 deaths were observed. This study highlights the need for mechanistic studies behind the effect of BCG vaccination on COVID-19, and for clinical evaluation of the effectiveness of BCG vaccination to protect from severe COVID-19.