Exercising caution in correlating COVID-19 incidence and mortality rates with BCG vaccination policies due to variable rates of SARS CoV-2 testing

Janine Hensel; Daniel J McGrail; Kathleen M McAndrews; Dara Dowlatshahi; Valerie S LeBleu; Raghu Kalluri

The copyright holder for this preprint (which was not peer-reviewed) is . https://doi.org/10.1101/2020.04.08.20056051 doi: medRxiv preprint COV-19 cases per million (Figure 2D) . The number of COVID-19 cases per million was significantly lower in countries with a current universal BCG policy and low CoV-2 testing rates ( Figure 2D ). For mortality rates in high CoV-2 testing countries, there was a significant reduction in countries with current BCG vaccination policies, but no difference was observed in countries with current BCG vaccination policies and low CoV-2 testing rates ( Figure 2E) . Univariate regression analysis for number of COVID-19 cases per million in high-testing nations indicated that testing rate, percent heart deaths, and urban population remained as significant co-variates (Figure 2F) , though none were significantly different based on a nation's vaccination policy (one-way ANOVA p values of 0.17, 0.14, and 0.27, respectively). Univariate regression of percent mortality in high testing nations did not reveal any significant co-variates ( Figure 2G) . The distinct suppliers for the BCG vaccines did not correlate with number of COVID-19 cases and mortality, largely because of the scarcity in available data ( Figure 2H ).