Anti-A and SARS-CoV-2: An Intriguing Association

Background Blood groups and anti-A isohemagglutinin may be involved in susceptibility to SARS-CoV-2 infection.Materials and Methods We retrospectively studied 268 COVID-19 convalescent plasma donors and 162 COVID-19 inpatients (total 430 subjects, confirmed by RT-PCR) and 2,212 healthy volunteer first-time blood donors as a control group. These were further divided into two groups: those with anti-A (blood types O and B) and those without it (types A and AB). Titres of nucleoproteins, and neutralizing SARS-CoV-2 antibody were measured in the convalescent plasma donors and inpatients. Multivariate logistic regression and non-parametric tests were applied.Results Persons having types O or B showed less infection prevalence than those of types A or AB (OR = 0 center dot 62, 95% CI 0 center dot 50-0 center dot 78; P < 0 center dot 001), but there was no difference when COVID-19 inpatients were analysed. Immunoglobulins M, G and A were lower in COVID-19 subjects of types O or B group than those of A or AB (0 center dot 16 vs. 0 center dot 19; P = 0 center dot 03, 2 center dot 11 vs. 2 center dot 55; P = 0 center dot 02, 0 center dot 23 vs. 0 center dot 32; P = 0 center dot 03, respectively).Conclusion In this retrospective cohort, COVID-19 individuals were less likely to belong to blood types O and B, and also had lower SARS-CoV-2 antibody titres than A and AB individuals. COVID-19 severity did not associate with the blood groups.