BCG Vaccine in Relation To COVID-19 Morbidity and Mortality

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) significantly interrupts daily life activities leading to global social and economic disruption. The infected cases and deaths due to COVID-19 are continuously rising. The lower incidence of COVID-19-cases among countries with Bacillus-Calmette-Guérin (BCG) vaccination background raises the possibility that BCG vaccine could be a protective against COVID-19. Here, we studied the prevalence of COVID-19-cases in relation to population received BCG vaccination. The collected data were compared at two different time points for proper validation and execution of appropriate association. Our investigations showed a correlative association between BCG vaccination and the number of COVID-19-cases. The association obtained can be supported by the fact that BCG vaccination is associated with an increase in trained immunity. This condition has been used previously to establish a protective effect by BCG vaccine against infections due to pathogens other than Tuberculosis (TB). The data obtained from this study could encourage the ongoing clinical studies regarding the use of BCG vaccine against COVID-19.