Does TB Vaccination Reduce COVID 19 Infection? No Evidence from a Regression Discontinuity Analysis
In the middle of the global COVID 19 pandemic, the BCG hypothesis, the prevalence and severity of the COVID 19 outbreak seems to be correlated with whether a country has a universal coverage of Bacillus Calmette Guerin (BCG) a vaccine for tuberculosis disease (TB) has emerged and attracted the attention of scientific community and media outlets. However, all existing claims are based on cross country correlations that do not exclude the possibility of spurious correlation. We merged country age level case statistics with the start/termination years of BCG vaccination policy and conducted a regression discontinuity and difference in difference analysis. The results do not support the BCG hypothesis.