COVID-19 Related Mortality: Is the BCG Vaccine Truly Effective?

The coronavirus disease 2019 (COVID-19) pandemic has become a worldwide emergency. In the attempt to search for interventions that would improve outcomes, some studies have looked at the potential benefit of BCG vaccination. These past studies have found a statistically significant reduction in COVID-19 related mortality in countries with a current universal bacille Calmette-Guérin (BCG) vaccination policy. However, just as the authors themselves noted, the nature of ecological studies make them very prone to the presence of several confounders. This paper took into account demographic differences, economic differences and the different stages of the pandemic in each country; gathering data from publicly available sources. It was found that no statistically significant difference exists in mortality rates between countries with a current or prior BCG vaccination policy when compared to those that never had such a program. Nevertheless, the immunostimulatory potential of the BCG vaccine might still prove useful in the development of future vaccines or other prophylactic measures.