COVID-19 Susceptibility among ABO/RH Blood Groups in Tamil Nadu Population: A Retrospective Case–Control Study

Abstract

Background: COVID-19 is a world pandemic with clinical manifestation from mild subclinical infection to severe illness. Literature suggests an evident correlation between the ABO blood group, Rhesus blood group, and COVID-19 in the recent past. The role of blood group in disease susceptibility and severity of COVID-19 varies in different geographical locations, as ABO blood group distribution varies among the human population with the impact of migration. Although various research have been done globally, scientific evidence with respect to the south Indian population remains limited, emphasizing the need for the present study to analyze the association of COVID-19 and blood groups in Tamil Nadu. Aim: The aim of this study was to analyze the potential susceptibility of COVID-19 among the blood groups (ABO and Rh type) in Tamil Nadu population. Materials and Methods: This was a noninterventional retrospective case–control study, with 500 patients who tested positive for COVID-19 being taken as the “cases,” while another 500 who tested negative were taken as the “controls.” The medical records, including the blood group and Rh factor, were collected from the government-recognized testing centers (Government Medical Hospital and Primary Health Centers, Tiruvallur, and Frontier Lifeline Hospital, Chennai) in Tamil Nadu, who came for COVID-19 screening by reverse transcriptase–polymerase chain reaction. The data were analyzed to associate its correlation with different blood groups. Results: Blood Group A showed significantly higher distribution among the cases (P = 0.030), and blood Groups O and B were significant among the controls (P = 0.026 and P = 0.000, respectively). Blood Group AB did not show any significant differences between the groups (P = 0.374). The odds ratio for AB, A, O, and B Groups for Rh (positive and negative) were shown to be 0.659, 0.591, 0.472, and 0.262, respectively, suggesting increased susceptibility toward Rh positive factor. Conclusion: In our study, blood Group A was found to be the most susceptible and blood Group O to be the least susceptible to COVID-19 in the Tamil Nadu population. In addition, the Rh positive factor showed more inclination toward COVID susceptibility than the Rh negative factor. ABO blood group may be considered a potential nonmodifiable and secondary risk factor for COVID-19 contributing to the disease pathobiology at immunological, biochemical, and physiological levels. Still, the intensity of their role and their exact mechanism in its association requires further exploration to validate the current findings.