Scientists who compared the 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.
[Editor’s note: Bloody types may have an impact on the severity of COVID-19 symptoms, according to a new study.][The June 17] report in the New England Journal of Medicine does not prove a blood type connection, but it does confirm a previous report from China of such a link.
Other scientists urged caution.
The evidence of a role for blood type is “tentative … it isn’t enough of a signal to be sure,” said Dr. Eric Topol, head of the Scripps Research Translational Institute in San Diego.
The study, involving scientists in Italy, Spain, Denmark, Germany and other countries, compared about 2,000 patients with severe COVID-19 to several thousand other people who were healthy or who had only mild or no symptoms. Researchers tied variations in six genes to the likelihood of severe disease, including some that could have a role in how vulnerable people are to the virus. They also tied blood groups to possible risk.
Many researchers have been hunting for clues as to why some people infected with the coronavirus get very ill and others, less so. Being older or male seems to increase risk, and scientists have been looking at genes as another possible “host factor” that influences disease severity.