Background: ABO blood groups may play a major role in the way COVID-19 spreads among same family members.

Objective: To determine the trends in the spread of COVID-19 in families according to their ABO blood groups. Explore the interrelationships between the main symptoms of COVID-19 infection.

Results: Two hundred forty-four subjects exposed to the SARS-CoV-2 virus participated in this study, 52 % males, age 29.64 ± 18.78 years. Forty-four percent of subjects have blood group A, 9 % were B, 7 % were AB and 32 % were O. Thirty-eight percent of polymerase chain reaction (PCR) positive subjects have blood group A and 37 % have blood group O. There was a significant association between the blood group of family members and the transmission of COVID-19, p ˂ 0.05.

There was also a significant relationship between the loss of taste, smell or both senses and anorexia, p ˂0.05. Headache was the most common symptom; 63 % of symptomatic patients who responded to this question.

 Conclusion: COVID-19 transmission among family members may follow the blood transfusion compatibility model.