Factors such as age and underlying health conditions such as diabetes can put you at a higher risk of contracting coronavirus, according to the U.S. Centers for Disease Control and Prevention. But one more factor that could affect your chances of getting coronavirus is your blood type.
People who have blood Type A were “associated with” a 45% “higher risk of acquiring COVID-19” compared to people with other blood types, according to a study published in the peer-reviewed New England Journal of Medicine by a team of European scientists.
Meanwhile, people with blood Type O, the most common blood type, less likely to get coronavirus as people with other blood types.
There are four main blood types: A, B, AB and O.
It’s not clear why blood type might influence susceptibility to severe disease. Dr. Robert Glatter, an emergency medicine physician at Lenox Hill Hospital in New York City, noted that genes that control blood type also play a role in the makeup of the surface of cells. Changes in cell-surface structure might influence the vulnerability of the cell to be infected by the new coronavirus, he said.
“We also know from previous research that blood type affects clotting risk,” he said, “and it’s now quite evident that critically ill patients with coronavirus demonstrate significant clotting.”
The new study was conducted by a multi-institution group of genetic researchers known as the Severe COVID-19 GWAS Group. They analyzed the genetics and blood types of more than 1,600 COVID-19 patients from Italy and Spain, as well as more than 2,200 healthy controls.
Besides the findings on blood type, the group also found that certain gene clusters were tied to higher odds of developing severe COVID-19 — one such cluster raised the risk by 77%, the team reported.
According to Glatter, the genetic insights from the European study could also offer up new targets in the search for a COVID-19 vaccine.
“Those who are not type A should not interpret this study to mean that they can let their guard down,” Silverstein, former president the American Society of Hematology, said. “Similarly, the data are not yet convincing enough to recommend that those with Type A need to do even more than what is recommended.”
“Everyone needs to pay attention to COVID-19 prevention by following well-accepted guidelines related to social distancing, face covering, hand-washing, and self-isolation and testing in the setting of possible COVID-related symptoms.”
A prior study published by the Southern University of Science and Technology in China, which has not been peer-reviewed, and a study by 23andMe, a privately held genetic-analysis company, pointed to similar results.
But even still, Silverstein urged people to take these findings “with a grain of salt.”
“This study, along with other studies from China and from 23andMe all suggest, but do not prove, a statistical association between non-O blood type with either risk of infection with the COVID-19 virus, or with risk of developing severe disease if infected.”
But the studies, he said, should prompt “more rigorous clinical studies as well as basic science studies to probe the mechanisms by which ABO blood type and or ABO genes might influence coronavirus ability to infect cells or the body’s immune response to the virus.”
Blood types B and AB are not as widespread, making up 11% and 5% of the population respectively. The risk of a severe COVID-19 course for such patients could lie somewhere in between that of patients with types 0 or A, according to the study.