ABO blood group does not influence the level of anti-SARS-CoV-2 antibodies in convalescent plasma donors

Background The association of the ABO blood group with COVID-19 disease has been confirmed by several studies, with the blood group A patients being more susceptible and prone to a more severe clinical course of the disease. Additionally, several authors also addressed the association of ABO-types and the levels of anti-SARS-CoV-2 antibodies in convalescents, mostly supporting a theory that the non-O blood group convalescents present with higher levels of anti-SARS-CoV-2 antibodies. Study Design and Methods Since previous findings were based on small convalescent cohorts, we quantified the anti-SARS-CoV-2 antibody levels in a total of 3187 convalescent plasma donors with three commercial serological and one standard neutralizing antibody test. The majority of donors had undergone a mild form of the disease and the median time of sampling was 66 days after diagnosis. Results None of the antibody quantitation results showed any significant association with the ABO blood group types. The same result was evident in the subgroup of vaccinated individuals (n = 370) and the subgroups when stratified according to post-COVID-19 periods (0-60, 60-120, and 120-180 days). Conclusion In conclusion, we found no evidence to confirm that the ABO blood group types influence the level of SARS-CoV-2 antibody response in COVID-19 convalescent plasma donors.