Blood-Type-A is a COVID-19 infection and hospitalization risk in a Turkish cohort.

Abstract

We have shown in an ethnically homogenous Turkey cohort with more than six thousand cases and 25 thousand controls that ABO blood types that contain anti-A antibody (O and B) are protective against COVID-19 infection and hospitalization, whereas those without the anti-A antibody (A and AB) are risks. The A+AB frequency increases from 54.7% in uninfected controls to 57.6% in COVID-19 outpatients, and to62.5% in COVID-19 inpatients. The odds-ratio (OR) for lacking of anti-A antibody risk for infection is 1.16 (95% confidence interval (CI) 1.1-1.22, and Fisher test p-value 1.8 ×10−7). The OR for hospitalization is 1.23 (95%CI 1.06-1.42, Fisher test p-value 0.005). A linear regression treating controls, outpatients, inpatients as three numerical levels over anti-A antibody leads to a p-value of 5.9 ×10−9. All these associations remain to be statistically significant after conditioning over age, even though age itself is a risk for both infection andhospitalization. We also attempted to correct the potential effect from vaccination, even thoughvaccination information is not available, by using the date of the data collection as a surrogate to vaccination status. Although no significant association between infection/hospitalization with Rhesus blood system was found, forest plots are used to illustrate possible trends.