17 July 2023

Researchers have revealed new insights into the link between blood group A and increased infection with SARS-CoV-2.

Blood group antigens have been widely investigated for their potential as risk factors for COVID infection. Patterns have emerged, but the mechanisms influencing these patterns are not fully understood, according to Dr Sean Stowell of Harvard Medical School, Boston, USA, and colleagues.

In this study, the team noticed that the receptor binding domain of SARS-CoV-2, which allows the virus to bind to cells, has similarities with human galectins – proteins involved in the immune response.

In lab experiments, the team found that the receptor binding domains of SARS-CoV-2, including Delta and Omicron variants, showed a preference for blood group A.

“Not only did each receptor binding domain recognise blood group A,” the team write in Blood, “but each SARS-CoV-2 virus likewise displayed a preferential ability to infect blood group A expressing cells.”

“These results demonstrate that SARS-CoV-2 can engage blood group A, providing a direct link between ABO(H) blood group expression and SARS-CoV-2 infection,” they report.

Dr Stowell said: “We show that the part of the SARS-CoV-2 spike protein that’s key to enabling the virus to invade cells displays affinity for blood group A cells, and the virus in turn also shows a preferential ability to infect blood group A cells.”

He added: “Among a group of several thousand people, some studies suggest that those with blood group A may be 20% more likely to be infected after exposure to SARS-CoV-2 compared with those who have blood group O.

“But people with blood group O can still contract the virus and may transmit it to others. Moreover, factors such as age and chronic conditions like heart disease rank higher than blood type in determining individuals’ risk for severe SARS-CoV-2 infection.”


Wu SC, Arthur CM, Jan HM, Garcia-Beltran WF, Patel KR, Rathgeber M, Verkerke H, Cheedarla N, Jajosky RP, Paul A, Neish AS, Roback JD, Josephson C, Wesemann D, Kalman D, Rakoff-Nahoum S, Cummings RD, Stowell SR.  (2023) “Blood Group A Enhances SARS-CoV-2 Infection.” Blood, doi: 10.1182/blood.2022018903

Link: https://ashpublications.org/blood/article/doi/10.1182/blood.2022018903/496471/Blood-Group-A-Enhances-SARS-CoV-2-Infection   

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