Lewis and ABO histo‐blood types and the secretor status of patients hospitalized with COVID‐19 implicate a role for ABO antibodies in susceptibility to infection with SARS‐CoV‐2

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) targets the respiratory and gastric epithelium, causing coronavirus disease 2019 (COVID‐19). Tissue antigen expression variations influence host susceptibility to many infections. This study aimed to investigate the closely linked Lewis (FUT3) and ABO histo‐blood types, including secretor (FUT2) status, to infections with SARS‐CoV‐2 and the corresponding severity of COVID‐19. STUDY DESIGN AND METHODS: Patients (Caucasians, n = 338) were genotyped for ABO, FUT3, and FUT2, and compared to a reference population of blood donors (n = 250,298). The association between blood types and severity of COVID‐19 was addressed by dividing patients into four categories: hospitalized individuals in general wards, patients admitted to the intensive care unit with and without intubation, and deceased patients. Comorbidities were considered in subsequent analyses. RESULTS: Patients with blood type Lewis (a−b−) or O were significantly less likely to be hospitalized (odds ratio [OR] 0.669, confidence interval [CI] 0.446–0.971, OR 0.710, CI 0.556–0.900, respectively), while type AB was significantly more prevalent in the patient cohort (OR 1.519, CI 1.014–2.203). The proportions of secretors/nonsecretors, and Lewis a+ or Lewis b+ types were consistent between patients and controls. The analyzed blood groups were not associated with the clinical outcome as defined. DISCUSSION: Blood types Lewis (a−b−) and O were found to be protective factors, whereas the group AB is suggested to be a risk factor for COVID‐19. The antigens investigated may not be prognostic for disease severity, but a role for ABO isoagglutinins in SARS‐CoV‐2 infections is strongly suggested.