ABSTRACT

Background: The lower COVID-19 related mortality observed in countries with a universal Bacillus Calmette-Guérin (BCG) vaccination policy led to the belief that the vaccine potentially has a protective role COVID-19. This study estimated the effect of the mean percentage of BCG vaccination coverage among infants, from 2010 to 2018, on the change in the mean weekly number of COVID-19 related deaths per million population whilst considering for the confounders of population density, elderly and urban proportions of the population.

Methods: The mean weekly number of COVID-19 related deaths per million population in 52 countries was regressed against the mean percentage of BCG coverage among infants from 2010 to 2011, population density per km2, percentages of urban and elderly (above 65-year of age) population in those countries in a multiple linear regression analysis.

Results: A significant regression model (F (4, 46)= 3.0941, p= 0.02) with an R2 of 0.319 was calculated. The mean number of weekly COVID-19 related deaths decreased by 0.179 with every 1% increase in the mean BCG coverage among infants from 2010 to 2018 (p=0.018) and increased by 0.013 (p=0.506), 0.189 (p=0.593), and 0.113 (p=0.469) when the mean number of people living per km2, percentage of elderly population, and percentage of urban population increased by 1 respectively.

Conclusions: There seems to be a statistically significant correlation between BCG vaccination coverage among infants and reduced COVID-19 related mortality. However, this relationship in no way represents conclusive scientific evidence and further detailed studies are warranted before the BCG can be recommended as protective against COVID-19