Home 2 Forums Covid -19 Blood Type Linked to COVID-19?


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    Sunil Kumar

    Quick Review
    First, let’s review the blood type basics. Your blood type is determined by the presence or absence of specific antigens (A and B) on the surface of the red blood cells and antibodies (A and B) in the plasma (American Red Cross, 2020). In addition to the A and B antigens and antibodies, there is a protein called the Rh factor, which
    Blood Type Linked to COVID-19?
    Research conducted on the first severe acute respiratory syndrome coronavirus-1 (SARS-CoV-1) found the anti-A antibody in people with blood group O or B may block the interaction between the virus and the receptor for angiotensin converting enzyme 2 (ACE2) found in cells, a mechanism for virus transmission (Guillon et al., 2008). SARS-CoV-2 also binds to ACE2 and therefore, may also be affected by the anti-A antibody. Additional studies found patients with blood group O have reduced levels of factor VIII and von Wilebrand factor, potential determinants which may provide a protective effect against vascular abnormalities in the pulmonary system (Hoiland et al., 2020).

    A study conducted in the earlier days of the SARS-CoV-2 pandemic by Zhao et al. (2020) evaluated 2,173 patients and found the ABO blood group to be a biomarker for COVID-19 susceptibility. Their research showed blood group A individuals had a higher risk for COVID-19 and blood group O was associated with a lower risk for the infection compared with non-O blood groups. This study had several limitations in that the sample size was small and the control population lacked information on subject age, sex and chronic medical conditions, preventing a proper analysis to adjust for these factors.

    Two recent studies were published this month (October 2020) in the journal Blood Advances supporting the theory that individuals with blood type O are at a lower risk for contracting COVID-19 and severe coronavirus illness.

    The first investigation led by Hoiland et al. (2020) evaluated whether ABO blood groups are associated with different severities of COVID-19. This was a multicenter retrospective analysis and prospective observational sub-study of critical care patients (n = 95). Their investigation found a higher proportion of COVID-19 patients with blood group A or AB required mechanical ventilation and continuous renal replacement therapy (CRRT) and had a longer intensive care unit (ICU) stay (13.5 days) compared with patients with blood group O or B. Biomarkers of renal (serum creatinine) and hepatic dysfunction (AST, ALT) were higher in blood Group A or AB patients. These results indicate severe lung impairment as well as worsening kidney and liver disease. Inflammatory cytokines did not differ between patients with blood group A or AB versus O or B and overall hospital length of stay did not differ between groups. This study has several limitations. First, as a retrospective analysis of observational data, the investigators could not prove causality. Second, the sample size was small, lacking statistical power. In addition, the titer of anti-A antibodies can affect COVID-19 severity and these levels were not analyzed, but instead inferred from blood group data.

    The second study conducted in Denmark by Barnkob et al. (2020) was a large retrospective cohort analysis designed to determine the influence of common blood types on virus susceptibility. The analysis compared over 473,000 people with COVID-19 to more than 2.2 million people in the general population. Of the COVID-19 positive individuals, considerably fewer blood type O individuals were found compared to a higher percentage of A, B, and AB individuals. There was no difference between ABO blood groups and clinical severity of COVID-19 for non-hospitalized patients versus hospitalized patients or for deceased patients versus living patients. The investigators concluded that blood group O is associated with reduced susceptibility to SARS-CoV-2 infection compared to type A, B and AB. However, ABO blood types did not correlate with rates of hospitalization or death following infection.


    • This topic was modified 3 months, 3 weeks ago by Sunil Kumar.
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