  Among the many aspects that characterize the COVID-19 pandemic, two seem
particularly challenging to understand: (i) the great geographical differences
in the degree of virus contagiousness and lethality which were found in the
different phases of the epidemic progression, and (ii) the potential role of
the infected people's blood type in both the virus infectivity and the
progression of the disease. A recent hypothesis could shed some light on both
aspects. Specifically, it has been proposed that in the subject-to-subject
transfer SARS-CoV-2 conserves on its capsid the erythrocytes' antigens of the
source subject. Thus these conserved antigens can potentially cause an immune
reaction in a receiving subject that has previously acquired specific
antibodies for the source subject antigens. This hypothesis implies a blood
type-dependent infection rate. The strong geographical dependence of the blood
type distribution could be, therefore, one of the factors at the origin of the
observed heterogeneity in the epidemics spread. Here, we present an
epidemiological deterministic model where the infection rules based on blood
types are taken into account and compare our model outcomes with the exiting
worldwide infection progression data. We found an overall good agreement, which
strengthens the hypothesis that blood types do play a role in the COVID-19
infection.
