Variations on a theme: New approaches to examine SARS-CoV-2 variants and their ABO connections

Many studies have reported an association between ABO blood group and COVID-19. People who are blood group A tend to have a higher infection rate and a worse course of disease than people who are blood group O. However, for the SARS-CoV-2 virus variants (UK, South Africa, Brazil), the association of ABO blood group and COVID-19 remains unclear. Here, we propose to explore reasons behind this association and whether these are the same for the variant viruses. One reason for the association of COVID-19 with blood group could relate to the 'sugars' that make up the ABO blood group. We have different ABO sugars in our bodies depending on our blood group (either A, B, AB or O). In A, B or AB people these sugars are on cells in the nasal passages and lung and may be used by the virus to enter our bodies and infect these cells. Another reason that ABO blood group may influence COVID-19 is through ABO antibodies that are produced 'naturally' in people depending on their blood group. (We produce ABO antibodies to the ABO sugars that we do not have. For instance, ABO-O people make antibodies to A and B sugars vs ABO-A people make antibodies only to B sugars). ABO antibodies could protect from infection by binding to the virus making it harder to infect cells. Both of these possibilities may be important and may happen together. Working with scientists and clinicians around the world, we will use special tools to: (1) study the binding of the SARS-CoV-2 virus (and variants) to ABO blood group sugars, and (2) measure ABO antibodies in the blood of COVID-19 patients (with known variant infection) and their binding to the virus. If we can understand how ABO blood group affects COVID infections, it may be possible to help guide better clinical treatment or preventative strategies. For instance, an understanding of the connection between ABO and COVID-19 could lead to new treatments for COVID-19 by blocking ABO sugars or by stimulating more ABO antibodies.