Mandated Bacillus Calmette-Guérin (BCG) vaccination predicts flattened curves for the spread of COVID-19

Martha K Berg; Qinggang Yu; Cristina E Salvador; Irene Melani; Shinobu Kitayama

We estimated a linear mixed model of the natural log-transformed number of deaths, controlling for the same control variables as above. As in the analysis on confirmed cases, we found a significant main effect of day, b = 0.168, p < .001, reflecting an exponential increase in deaths over time (Table 1-B) . This increase was qualified by a significant interaction between day and BCG policy status. Specifically, the growth rate of COVID-19 related deaths was significantly less in countries with mandated BCG vaccinations, compared to countries without mandated BCG vaccinations, b = -0.038, p < .001 ( Fig. 1-C and D) . This effect was independent of the cultural dimensions mentioned above ( Supplementary Results 1-B) . Countries that once had such policies but terminated them before 2000 were no different in growth rate from those that never instituted mandatory BCG, b = -0.003, p = .829. Fig. 2