Before revision:  The vaccination rate fell from 92\% to 2\% . I compare the numbers of COVID-19 cases and hospitalizations for cohorts born just before and just after that change . I find no statistically significant differences, and I can reject small BCG effects. Thus,receiving the BCG vaccine at birth does not seem to have a protective effect against COVID-19. ] ]\\%DIF > confidence that universal BCG vaccination reduces the number of cases by more than 20\% and the number of hospitalizations by more than 24\%.
After revision:  The vaccination rate fell from 92\% to 2\% . I compare the numbers of COVID-19 cases and hospitalizations for cohorts born just before and just after that change , representing 1,026,304 and 1,018,544 individuals, respectively. We used regression discontinuity to assess the effect of BCG vaccination on Covid-19 related outcomes. This method used on such a large population allows for a high precision that would be hard to achieve using a classical randomized controlled trial. The odds ratio for Covid-19 cases and Covid-19 related hospitalizations were 0.9997 (CI95: ] ]\\%DIF > confidence that universal BCG vaccination reduces the number of cases by more than 20\% and the number of hospitalizations by more than 24\%.