Coronavirus infection and ABO blood grouping: Correlation or coincidence?

Background: Association between the ABO blood group and patient outcomes in COVID-19 patients is still unexplored. A known association may help to understand possible risks in advance to the management of such COVID-19 patients. The present study was designed to test such association if there is any, between the ABO blood group and the severity of COVID-19 patients. Methods: The present hospital-based observational study was conducted at a COVID-19 dedicated tertiary care hospital in North India over a period of six months during the first wave of the pandemic in the country. Five hundred consecutive patients, who tested positive for COVID-19 using RT-PCR on oropharyngeal/nasopharyngeal swabs, admitted to the hospital were included in the study. ABO and Rhesus (Rh) blood grouping was done on leftover hematology blood samples using gel column agglutination technology. Required clinical details of patients including age, gender, clinical symptoms, comorbidities, outcomes, etc., were obtained from the patient's case sheets. Results: The most common blood group was 'B' (42.8%) followed by 'O' (23.4%), and 'A' (22.4%) while the least common was 'AB' (11.4%). Rh positive was seen in 96.2% while 3.8% were negative. Baseline characteristics were comparable including length of hospital stay, duration of symptoms, and associated comorbid illnesses. The need for intensive care unit (ICU) admissions (P = 0.05) and intubations (P = 0.20) was similar across all four blood groups. Differences in the severity of COVID-19 disease and mortalities among the groups were non-significant. Conclusion: There was no observed association found between the ABO blood group and COVID-19 infection requiring hospitalization, ICU admission, intubation, and outcomes. However, there was a higher proportion of breathlessness and the presence of at least one comorbidity in blood group O as compared to others.