key: cord-1055309-espg6fey authors: Dzik, Sunny; Eliason, Kent; Morris, Edward B.; Kaufman, Richard M; North, Crystal M. title: COVID‐19 and ABO blood groups date: 2020-06-19 journal: Transfusion DOI: 10.1111/trf.15946 sha: 39704de8e409c6cd6d1ae1ae8ced85816d7f7bfd doc_id: 1055309 cord_uid: espg6fey nan likely that genetic factors will prove to be relevant to the host thromboinflammatory response. Recently, investigators from China reported that ABO type was strongly statistically associated not only with acquiring SARS-CoV-2 infection but also with survival following infection. Zhao et al [1] compared ABO distributions on 1,775 patients with SARS-CoV-2 infection in China with 3,694 ABO types from a background healthy population. Of note, their reference population was not a cohort of uninfected patients admitted to the same hospital, but rather was a background reference population of 'normal individuals' from Wuhan. (The details of that cohort were not reported.) They found that blood group O was less common among infected individuals (25.8%) compared with healthy population-based controls (33.8%) and that group A was more common among infected individuals (37.7%) compared with healthy population-based controls (32.2%), p < 0.001. They also reported that, among 206 COVID-19 patients who died, blood group O was significantly less common (25.2%) compared with their reference population (33.8%, p=0.014). Their data are shown in the Although there are only four basic ABO phenotypes, they derive from 235 known ABO gene variants which vary among different ethnic population groups. [3] To explore whether ABO phenotype might be associated with fatal outcome in a cohort This article is protected by copyright. All rights reserved. This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record Growing evidence suggests that SARS-CoV-2 infection that is serious enough to require hospitalization may disproportionately affect racial and ethnic minorities in the USA. [4] Since ABO blood group varies by ethnicity, this might influence the observed ABO distribution when comparing infected versus uninfected cohorts. We explored this hypothesis by comparing the distribution of ABO blood type among MGH and BWH patients with documented SARS-CoV-2 infection compared with 5,840 randomly selected patients who were hospitalized at MGH and BWH during March and April 2019 in the pre-COVID era. The proportion of cases and controls contributed by the two hospitals was the same. As shown in the Table, we found a non-significant slightly higher proportion of blood group O individuals among our cohort with SARS-CoV-2 infection, p=0.1079. One possible explanation for the slightly higher proportion of group O in COVID-19 patients may be that, in Boston, the pandemic has disproportionately affected those of Latin or Hispanic descent among whom group O is more frequent [5] . The ABO blood group polymorphism has been shown to be associated with survival Among MGH-BWH patients, a comparison of ABO distribution among COVID-infected versus MGH pre-COVID era patients is X 2 = 6.08, p=0.1079 Erythrogene: a database for in-depth analysis of the extensive variation in 36 blood group systems in the 1000 United States Center for Disease Prevention and Control (CDC) ABO and Rh(D) phenotype frequencies of different racial/ethnic groups in the United States Cytoadherence in paediatric malaria: ABO blood group, CD36, and ICAM-1 expression and severe Plasmodium falciparum infection The ABO blood group locus and a chromosome 3 gene cluster associate with SARS-CoV-2 respiratory failure in an Italian-Spanish genome-wide association analysis