A direct link was found between SARS-COV-2, the virus that causes COVID-19, and Blood group A, and the virus also preferentially infects blood group A cells, according to a study published in the journal Blood.
Earlier in the pandemic, researchers suggested that blood type increases one’s chance of contracting COVID. One work suggested that people with blood group A seemed more vulnerable to infection with coronavirus than those with blood group O. However, no study has identified the mechanism that explains the risk imbalance between blood groups.
For this study, Dr. Sean R. Stowell of Harvard Medical School and colleagues carried out laboratory experiments to find an explanation of how blood type plays a role in COVID-19 risk.
Dr. Stowell and colleagues found in the lab that each blood group had different proteins or antigens that caused it to react differently to the COVID-19 virus. According to the researchers, the receptor binding domain of SARS-COV-2 exhibited specificity for blood group A. In addition, the researchers found that each SARS-CoV-2 virus likewise displayed a preferential ability to infect blood group A-expressing cells.
“Blood group A cells were more likely to be infected with SARS-CoV-2 when compared with blood group O cells,” Dr. Stowell said.
Furthermore, the researchers found that adding a special protein (galectin) that inhibits SARS-CoV-2 from recognizing certain blood antigens blocked the virus’ preference for infecting blood group A cells but did not affect blood group O cells. In addition, when they added a galectin that didn’t block the recognition of blood group antigens, they found no infection-inhibiting effects on either A or O cells.
On further experimentation, the researchers found that the Omicron strain of SARS-CoV-2 had an even stronger preference for infecting blood group A cells than the original virus.
The researchers cautioned that although their findings provide a mechanism for how blood group A may directly influence the risk of infection with SARS-CoV-2, people with blood group O should not assume they have a free pass from the virus but rather should take precautions against SARS-CoV-2 infection.
“Blood group is one of many variables that influence one’s likelihood of becoming infected following exposure to SARS-CoV-2,” Dr. Stowell said. “Regardless of their blood group, individuals should be fully vaccinated against COVID-19 and should continue to take other preventive measures appropriate to their risk level.”
Source: News Medical
Journal Source: BLOOD