ABO blood type association with SARS-CoV-2 infection mortality: A single-center population in New York City

Transfusion. 2021 Apr;61(4):1064-1070. doi: 10.1111/trf.16339. Epub 2021 Mar 5.


Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has a variable clinical course with significant mortality. Early reports suggested higher rates of SARS-CoV-2 infection in patients with type A blood and enrichment of type A individuals among COVID-19 mortalities.

Study design and methods: The study includes all patients hospitalized or with an emergency department (ED) visit who were tested for SARS-CoV-2 between March 10, 2020 and June 8, 2020 and had a positive test result by nucleic acid test (NAT) performed on a nasopharyngeal swab specimen. A total of 4968 patients met the study inclusion criteria, with a subsequent 23.1% (n = 1146/4968) all-cause mortality rate in the study cohort. To estimate overall risk by ABO type and account for the competing risks of in-hospital mortality and discharge, we calculated the cumulative incidence function (CIF) for each event. Cause-specific hazard ratios (csHRs) for in-hospital mortality and discharge were analyzed using multivariable Cox proportional hazards models.

Results: Type A blood was associated with the increased cause-specific hazard of death among COVID-19 patients compared to type O (HR = 1.17, 1.02-1.33, p = .02) and type B (HR = 1.32,1.10-1.58, p = .003).

Conclusions: Our study shows that ABO histo-blood group type is associated with the risk of in-hospital death in COVID-19 patients, warranting additional inquiry. Elucidating the mechanism behind this association may reveal insights into the susceptibility and/or immunity to SARS-CoV-2.

Keywords: ABO; SARS-CoV-2.

Publication types

  • Clinical Trial

MeSH terms

  • ABO Blood-Group System
  • Aged
  • Aged, 80 and over
  • COVID-19 / blood*
  • COVID-19 / mortality*
  • COVID-19 / therapy
  • Disease-Free Survival
  • Female
  • Hospital Mortality*
  • Hospitals*
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • New York City / epidemiology
  • Retrospective Studies
  • SARS-CoV-2 / metabolism*
  • Survival Rate


  • ABO Blood-Group System