Study ties blood type to COVID-19 risk; O may help, A hurt

A genetic analysis of COVID-19 patients suggests that blood type might influence wher someone develops severe disease.

Scientists who compared genes of thousands of patients in Europe found that those who had Type A blood were more likely to have severe disease while those with Type O were less likely.

Wednesday’s report in New England Journal of Medicine does t prove a blood type connection, but it does confirm a previous report from China of such a link.

“Most of us discounted it because it was a very crude study,” Dr. Parameswar Hari, a blood specialist at Medical College of Wisconsin, said of report from China. With new work, “w I believe it,” he said. “It could be very important.”

Or scientists urged caution.

evidence of a role for blood type is “tentative ... it isn’t eugh of a signal to be sure,” said Dr. Eric Topol, head of Scripps Research Translational Institute in San Diego.

study, involving scientists in Italy, Spain, Denmark, Germany and or countries, compared about 2,000 patients with severe COVID-19 to several thousand or people who were healthy or who had only mild or symptoms. Researchers tied variations in six genes to likelihood of severe disease, including some that could have a role in how vulnerable people are to virus. y also tied blood groups to possible risk.

Most genetic studies like this are much larger, so it would be important to see if or scientists can look at or groups of patients to see if y find same links, Topol said.

Many researchers have been hunting for clues as to why some people infected with coronavirus get very ill and ors, less so. Being older or male seems to increase risk, and scientists have been looking at genes as ar possible “host factor” that influences disease severity.

re are four main blood types — A, B, AB and O — and “it’s determined by proteins on surface of your red blood cells,” said Dr. Mary Horowitz, scientific chief at Center for International Blood and Marrow Transplant Research.

People with Type O are better able to recognize certain proteins as foreign, and that may extend to proteins on virus surfaces, Hari explained.

During SARS outbreak, which was caused by a genetic cousin of coronavirus causing current pandemic, “it was ted that people with O blood type were less likely to get severe disease,” he said.

Blood type also has been tied to susceptibility to some or infectious diseases, including cholera, recurrent urinary tract infections from E. coli, and a bug called H. pylori that can cause ulcers and stomach cancer, said Dr. David Valle, director of Institute of Genetic Medicine at Johns Hopkins University.

Bottom line: “It’s a provocative study. It’s in my view well worth publishing and getting out re,” but it needs verification in more patients, Valle said.