The effects of blood group types on the risk of COVID-19 infection and its clinical outcome

Turk J Med Sci. 2020 Jun 23;50(4):679-683. doi: 10.3906/sag-2005-395.


Background/aim: COVID-19 (Coronavirus disease of 2019) is an infectious disease outbreak later on declared as a pandemic, caused by the SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2). It spreads very rapidly and can result in severe acute respiratory failure. The clinical studies have shown that advanced age and chronic diseases increase the risk of infection. However, influence of the blood groups on COVID-19 infection and its outcome remains to be confirmed. The aim of this study is to investigate whether there exists a relationship between the blood groups of the patients and risk of SARS-CoV-2 infection and the clinical outcomes in COVID-19 patients

Material and method: 186 patients with PCR confirmed diagnosis of COVID-19 were included in this study. Age, sex, blood groups, comorbidities, need for intubation and intensive care unit follow up and mortalities of the patients were analyzed retrospectively. 1881 healthy individuals, who presented to the Hacettepe University Blood Bank served as the controls.

Results: The most frequently detected blood group was blood group A (57%) amongst the COVID-19 patients. This was followed by blood group O (24.8%). The blood group types did not affect the clinical outcomes. The blood group A was statistically significantly more frequent among those infected with COVID-19 compared to controls (57% vs. 38%, P < 0.001; OR: 2.1). On the other hand, the frequency of blood group O was significantly lower in the COVID-19 patients, compared to the control group (24.8% vs. 37.2%, P: 0.001; OR: 1.8).

Conclusions: The results of the present study suggest that while the blood group A might have a role in increased susceptibility to the COVID-19 infection, the blood group O might be somewhat protective. However, once infected, blood group type does not seem to influence clinical outcome.

Keywords: Blood groups; COVID-19; SARS-COV-2; susceptibility; clinical outcome.

MeSH terms

  • ABO Blood-Group System*
  • Adult
  • Aged
  • Aged, 80 and over
  • COVID-19 / blood*
  • COVID-19 / epidemiology*
  • COVID-19 / mortality
  • COVID-19 / therapy
  • Case-Control Studies
  • Female
  • Humans
  • Intensive Care Units / statistics & numerical data
  • Intubation, Intratracheal / statistics & numerical data
  • Male
  • Middle Aged
  • Prognosis
  • Respiration, Artificial / statistics & numerical data
  • Retrospective Studies
  • Risk Factors
  • SARS-CoV-2
  • Severity of Illness Index
  • Young Adult


  • ABO Blood-Group System