The anecdotal evidence for a positive impact of the Bacille Calmette Guerin (BCG) vaccine on COVID-19 disease comes from an ecological study in which morbidity and mortality rates from COVID-19 in various countries are compared in relation to their use of BCG vaccine in the past (Miller et al, medRxiv preprint doi: https://doi.org/10.1101/2020.03.24.20042937 not peer- reviewed). The […]