Childhood Bacille Calmette-Guerin Vaccination and Its Association With Less Severe COVID-19 Pneumonia

INTRODUCTION: The potential for Bacille Calmette-Guerin vaccination to mitigate COVID-19 severity and perhaps infection susceptibility has been hypothesized, attracting global attention given its off-target benefits shown in several respiratory viral infections. METHODS: In this retrospective study, patients with laboratory-confirmed COVID-19 from Wuhan Pulmonary Hospital, China were categorized into Bacille Calmette-Guerin‒vaccinated and nonvaccinated groups. Clinical records, demography, laboratory results, and chest computed tomography scans were extracted from electronic medical records and compared between the 2 groups. RESULTS: No adverse events were observed, except for an increased frequency of chills in the Bacille Calmette-Guerin‒vaccinated group compared with that in the unvaccinated group (p=0.014). There were no significant differences in oxygen demand for breathing, computed tomography scans, treatments, or outcomes between the 2 groups. However, Bacille Calmette-Guerin‒vaccinated group had significantly less severe pneumonia (p=0.028) and milder deficiency in liver function, consistent with a lower death rate than in the unvaccinated group. CONCLUSIONS: Bacille Calmette-Guerin vaccination received in childhood is associated with less severe COVID-19 pneumonia and milder liver function deficiency in addition to a lower death rate in Bacille Calmette-Guerin‒vaccinated patients than in nonvaccinated individuals.