Race may modify the association between blood type and COVID-19 infection.

This study aims to investigate the race/ethnicity-specific association between blood type and COVID-19 susceptibility during March, 2020 and December, 2021 using data from the electronic health record at the University of Chicago Medicine. The study population was stratified into four groups: non-Hispanic White, non-Hispanic Black, Hispanic, and other. Log-binomial generalized mixed model was used to estimate the relative risk (RR) and 95% confidence interval (CI). When compared to blood type O, type B was associated with positive COVID-19 test in Blacks (RR = 1.12, 95% CI: 1.02-1.23), Whites (RR = 1.28, 95% CI: 0.99-1.66), and Hispanic (RR = 1.36, 95% CI: 0.97-1.92).