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(NEXSTAR) – Two new studies suggest a link between people with type O blood and a decreased chance of contracting COVID-19, as well as milder symptoms for those who do.

It’s not yet clear what’s causing the statistical connection found in two studies released Wednesday, one in Denmark and one in Canada, and experts say more research is needed, according to CNN.

The Danish study found that people with type O blood made up only 38.4% of the 7,422 Danes who tested positive, despite people in that blood group making up 41.7% of the roughly 2.2 million untested people in the population.

People with type A blood, however, made up 44.4% of the infected patients, the study found, despite making up just 42.4% of the untested group.

The Canadian study looked at 95 patients who became critically ill with COVID-19 and examined their outcomes. Those with type A or type AB ended up needing treatment with a ventilator, compared to 61% when it came to patients with type O or B.

Those with type A or AB blood had a median stay in the intensive care unit of 13.5 days, compared to 9 days for those with type O or B, the study found.

More needs to be understood

Dr. Mypinder Sekhon, who authored the Canadian study and works in the intensive care unit at Vancouver General Hospital, told CNN the study is in the back of his mind when he evaluates patients, but says there must be “repeated findings across many jurisdictions” that show the same link to be considered a “definitive marker.”

“I don’t think this supersedes other risk factors of severity like age and co-morbities and so forth,” Sekhon said.

Dr. Torben Barington, the senior author of the Danish study, agrees that the findings have potential scientific interest when it comes to understanding COVID-19 and creating vaccines, but there are still a lot of unknowns.

“We do not know whether this is some kind of protection of group O, or whether it’s some kind of vulnerability in the other blood groups,” he told CNN.

Both studies were published in Blood Advances, a medical journal published by the American Society of Hematology.

Both doctors agree that the studies shouldn’t immediately change how people go about their daily lives.

“If one is blood group A, you don’t need to start panicking,” Dr. Sekhon said. “And if you’re blood group O, you’re not free to go to the pubs and bars.”