A genetic analysis of COVID-19 patients suggests that blood type might influence whether someone develops severe disease, per the AP. 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. The study in the New England Journal of Medicine does not prove a blood type connection, but it does back up 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 the Medical College of Wisconsin, said of the report from China. With the new work, “now I believe it,” he said. “It could be very important.” Other scientists urged caution.
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 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 factor. There are four main blood types— A, B, AB, and O. 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 the SARS outbreak, which was caused by a genetic cousin of the coronavirus causing the current pandemic, “it was noted that people with O blood type were less likely to get severe disease,” he said.
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