Association between ABO Blood Group System and the Severity of COVID-19 in the West Bank: A Case-control Study

Introduction: Several studies have examined risk factors for COVID-19, and there have been conflicting results regarding whether blood type influences the risk of COVID-19. Therefore, this study aimed to determine the association between the ABO blood group system and the severity of COVID-19 in the West Bank of Palestine.
Methods: A case-control study design was used, consisting of 169 cases and 169 controls who had undergone COVID-19 PCR testing in March 2021 in the West Bank, stratified according to their test results. A self-administered questionnaire in Arabic was used, which included the following parts: socio-demographic data, smoking status, seasonal flu, medical history of COVID-19, and the experience of COVID-19 cases. Both descriptive and analytical analyses were carried out. Binary logistic regression (Enter model) was used in the multivariate analysis to demonstrate the odds ratio.
Results: The study included 338 participants (169 cases and 169 controls) with a 95% response rate. Among the participants, 46.4% lived in the northern region (Nablus, Jenin, Qalqilya, Salfit, Tubas, Tulkarm). Blood group B was found to be more protective against COVID-19 than blood group A (AOR=0.40, CI=0.223-0.718). Blood group AB was also more protective against COVID-19 than blood group A (P < 0.05, AOR=0.316, CI=0.143-0.698). There was no statistically significant difference between blood group A and blood group O concerning the severity of symptoms or the composite outcomes of COVID-19.
Conclusion: There is an association between the ABO blood group and the risk of COVID-19. Nonetheless, the precise mechanism and severity of the effect vary, necessitating further investigation through larger and more intensively controlled studies.