Association between ABO blood groups and risk of COVID-19 infection: An umbrella review

Abstract

Numerous primary studies, systematic reviews, and meta-analyses have been conducted to examine the association between ABO blood groups and susceptibility to coronavirus disease 2019 (COVID-19) infection. The findings, however, are preliminary and contentious. As a result, the following umbrella review examines the relationship between ABO blood groups and the risk of COVID-19 infection. From December 9, 2020, to December 29, 2020, relevant articles were searched using Google Scholar, Google, and Cochrane systematic review databases. After eliminating duplicates and screening records based on article titles, abstracts, and full texts, four full article texts met the inclusion criteria. The data were analyzed using a narrative approach. This umbrella review suggests that blood group A may be a risk factor for COVID-19 infection and blood group O may be a protective factor; however, all studies included in this umbrella review reported significant heterogeneity across primary studies, which may explain inconsistent and discordant findings regarding the relationship between ABO blood groups and risk of COVID-19 infection, severity, and mortality outcomes, thereby limiting the findings. Thus, additional methodologically rigorous and experimental research and prospective cohort studies are warranted.