Explore the Possible Impact of BCG Vaccination Policy on the Morbidity, Mortality, and Recovery Rates due to COVID-19 Infection.

BACKGROUNDThe Coronavirus Disease-19 (COVID-19) is the new form of an acute infectious respiratory disease and has quickly spread over most continents in the world. Recently, it has been shown that Bacille Calmette-Guerin (BCG) might protect against COVID-19. This study aims to investigate the possible correlation between BCG vaccination and morbidity/mortality/recovery rate associated with COVID-19 infection. METHODSData of COVID-19 confirmed cases, deaths, recoveries, and population were obtained from https://www.worldometers.info/coronavirus/ (Accessed on 12 June, 2020). To have meaningful comparisons among countries mortality and recovery rates, we only choose those countries with COVID-19 infected cases at least 200. The Poisson regression and logistic regression were used to explore the relationship between BCG vaccination and morbidity, mortality and recovery rates. RESULTSAmong those 158 countries with at least 200 COVID-19 infected cases, there were 141 countries with BCG vaccination information available. The adjusted rates ratio of COVID-19 confirmed cases for Current BCG vaccination vs. non-Current BCG vaccination was 0.339 (with 95% CI= (0.338,0.340)). Moreover, the adjusted odds ratio (OR) of death and recovery after coronavirus infected for Current BCG vaccination vs. non-Current BCG vaccination were 0.258 (with 95% CI= (0.254,0.261)) and 2.151 (with 95% CI= (2.140,2.163)), respectively. CONCLUSIONSThat data in this study show the BCG might provide the protection against COVID-19, with consequent less COVID-19 infection and deaths and more rapid recovery. BCG vaccine might bridge the gap before the disease-specific vaccine is developed, but this hypothesis needs to be further tested in rigorous randomized clinical trials.