Does PCR Cycle Threshold for SARS-CoV-2 have Association with ABO Blood Group Types?

Introduction: Corona Virus Disease-19 (COVID-19) caused by the Severe Acute Respiratory Syndrome-Corona Virus-2 (SARSCoV-2) has led to a global pandemic. Currently, the standard method for the diagnosis of COVID-19 is the detection of SARSCoV-2 by Reverse Transcriptase Quantitative Polymerase Chain Reaction (RT-qPCR). Lower Cycle threshold (Ct) value of PCR is found to be associated with increased probability of progression to severe disease and infectivity. Blood group A individuals have been found to be more susceptible to infection by SARS-CoV-2 while that of O blood group have lower risk of infection. There has been growing scientific interest to obtain data which may characterise the susceptibility to COVID-19 infection and determine the risk factors which may be associated with progression and severity of the disease. Aim: To study the association of RT-qPCR Ct values for SARSCoV-2 with ABO blood group types. Materials and Methods: A prospective observational study was conducted at tertiary care centre in western Maharashtra, India where in a total of 116 symptomatic admitted patients between mid-July to mid-August 2020 and was found to be positive for SARS-CoV-2 by RT-qPCR were enrolled in the study. Ct values for pan-Sarbecovirus E-gene and SARSCoV-2 specific RdRP gene were recorded for each patient. In addition, all the patients were typed for ABO blood grouping. Distribution of different ABO blood group types in SARS-CoV-2 positive patients were analysed and was compared with blood groups in 882 non-COVID-19 blood donors comprising control group. Ct values for E and RdRP gene were also analysed in respect to different age group, gender and blood group types. Blood group records of voluntary healthy blood donors reporting at our centre between September to November 2019 were obtained. Results: Of the 116 patients, 33 (28.45%) comprised of type A, 34 (29.31%) of type B, 41 (35.34%) were of type O and remaining 8 (6.90%) had AB blood group type. Compared to the control group, no significant difference was noted in the distribution of ABO blood types in SARS-CoV-2 positive patients. Also, no statistical significance was found in the Ct values with respect to age, gender and different ABO blood group types. Conclusion: RT-qPCR Ct values for SARS-CoV-2 infection have no association with ABO blood group types.