Correlation between universal BCG vaccination policy and reduced mortality for COVID-19

Abstract COVID-19 has spread to most countries in the world. Puzzlingly, the impact of the disease varies in different countries. This variation is attributed to differences in cultural norms, mitigation efforts, and health infrastructure. Here, we propose that national differences in COVID-19 impact could be partially explained by different national policies with respect to Bacillus Calmette-Guérin (BCG) vaccination. BCG vaccination has been reported to offer broad protection from other respiratory infections besides tuberculosis. We compared BCG vaccination policies with the morbidity and mortality for COVID-19 for middle-high and high-income countries. We found that countries without universal policies of BCG vaccination (Italy, the Netherlands, USA) have been more severely affected compared to countries with universal and long-standing BCG policies. The difference cannot be accounted for by differences in disease onset, adoption of early social distancing policies, state of health services, nor income level. Reduced mortality suggests BCG vaccination could be a potential new tool in the fight against COVID-19.