Systematic review and meta-analysis of the susceptibility of ABO blood group to COVID-19 infection.

BACKGROUND: Numerous studies investigate the association between the ABO blood groups and the occurrence of COVID-19 infection; discordant findings were reported. Therefore, the purpose of this meta-analysis was to evaluate the existing evidence on the susceptibility of the ABO blood group to COVID-19 infection. METHODS: Systematically searched published articles in PubMed, Google Scholar, Scopus, and EMBASE between 1 st January 2020 and 21 st March 2021. After quality control and the exclusion of irrelevant studies, 16 studies were included in the final analysis. RESULTS: Although the random-effect meta-analysis revealed a large heterogeneity among studies, I 2 = 99.197 %. The pooled event rates and (95 % CIs) for A, O, B, and AB blood group were 0.459 (95 %CI: 0.358-0.441), 0.342 (95 %CI: 0.298-0.374), 0.180 (95 %CI: 0.150-0.214), and 0.076 (95 %CI: 0.055-0.127), respectively. These results indicated that the COVID-19 infection rate was higher in persons with blood group A > O > B > AB. Overall, the ABO blood group's vulnerability to COVID-19 infection was statistically significant (pooled p -value<0.001). CONCLUSION: This meta-analysis offers a further indication of blood group A individuals' vulnerability to COVID-19 infection, and blood type AB are linked to a lower risk of COVID-19 infection.