Scientists who compared the genes of thousands of patients in Europe found that those who had Type A blood were more likely to have a serious disease, while those with Type O were less and less likely.
Wednesday’s report in the New England Journal of Medicine does not prove a blood-type connection, but confirms an earlier report from China of such a link.
“Most of us discounted because it was a very crude study,” Dr. Parameswar Hari, a blood test specialist at the Wisconsin Medical College, said the report from China. With the new work, “now, I think,” he says. “It could be very important. ”
Other scientists urged caution.
Evidence of a role for the blood type is “provisional … it is not enough to” signal “to be sure,” said Dr. Eric Topol, head of the Institute’s Translational Research Scripps in San Diego.
The study, involving scientists in Italy, Spain, Denmark, Germany and other countries, against approximately 2,000 patients with severe COVID-19 to several thousand other people who were in good health or who had few or no symptoms. Researchers attached variations in the six genes for the likelihood of serious illness, including some that may have a role in how vulnerable people are to viruses. They also tied up possible risk blood groups.
Most genetic studies like this are much larger, so it would be important to see if other researchers look at the other patient groups to see if they find the same links, Topol said.
Many researchers have been hunting for clues as to why some people infected with the coronavirus become very sick and others, less. Older or male seems to increase the risk, and scientists have been researching genes as the “host factor that influences the severity of the disease.”
There are four main types of blood – A, B, AB and O – and “that it is determined by proteins on the surface of your red blood cells,” said Dr. Mary Horowitz, chief scientist at the International Blood Center and Research Bone Marrow.
Type O people are better able to recognize certain proteins as foreign, and that can extend to all of the proteins of the surface virus, Hari explained.
During the SARS epidemic, which was caused by genetics, the cousin of the coronavirus causing the current pandemic, “it was noted that people with O blood type were less likely to contract a serious illness,” he said.
Blood type has also been linked to susceptibility to certain other infectious diseases like cholera, urinary tract infections with E. coli, and a bug called H. pylori which can cause ulcers and stomach cancer , said Dr. David Valle, director of the Institute of Genetic Medicine at Johns Hopkins University.
Bottom line: “This is a provocative study. I think it’s really useful to publish and get out of here, “but it needs to be checked in addition to patients, Valle said.
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