Late Breaking Abstract - The affinity of haemoglobin for oxygen is not altered in the course of Covid-19

Context: An in silico modelling suggested that SARS-CoV-2 might bind to haemoglobin (Hb) The authors hypothesised that this phenomenon could lead to a decreased oxygen (02) binding and also haemolytic anemia (Liu & Li, ChemRxiv 2020) Although they were not supported by any experimental validation such as in vitro biochemical interaction, or any clinical observation, these conclusions were largely relayed in the media and social networks The aim of this study was to investigate if Hb affinity for 02 was altered in the course of Covid-19 Methods: In this retrospective, observational, single-center study, we compared the blood gas analyses of 100 Covid-19 patients (from March-April 2020) to those of 100 non Covid-19 patients (from March-April 2019) We also included in a third group 55 patients with carboxyhaemoglobin (HbCO) > 8% (positive controls with altered Hb affinity) P50 was corrected for body temperature, pH and PC02 Results: Patients were not statistically different for age or sex ratio in the Covid-19 and non Covid-19 groups Median P50 at baseline was 26 [25 2-26 8] versus 25 9 [24-27 3], respectively (p=0 42) As expected, it was lower in the high HbCO group: 22 5 [21 6-23 8] (p<0 0001) When considering the time course of P50, no significant difference was observed between Covid-19 and non Covid-19 groups, from day 1 to day 18 Median Hb concentration at beselinewas 14 g dl'1 [12 6-15 2] in the Covid-19 group versus 13 2 [11 4-14 7] in the non Covid-19 group (p=0 006) On the 24 Covid-19 patients displaying anemia, none of them exhibited obvious biological haemolysis Conclusion: There was no biological argument to support the hypothesis that SARS-CoV-2 could alter 02 binding to Hb