The spread of COVID-19 and the BCG vaccine: A natural experiment in reunified Germany

Summary The ‘BCG hypothesis' suggests that the Bacillus Calmette-Guérin (BCG) vaccine against tuberculosis limits severity of COVID-19. We exploit differential vaccination practices East Germany and West prior to reunification test this hypothesis. Using a difference in regression discontinuities (RD-DD) design centred on end universal West, we find differences COVID-19 across cohorts are insignificant or have wrong sign. document sharp cross-sectional discontinuity disease, which attribute limited mobility long-gone border disappears when control for social connectedness. Case death data after first lockdown 26 April does not display at former border, suggesting (as opposed BCG vaccination) played major role during initial outbreak.