A team of European scientists say they have found two genetic variations that may show who is more likely to get very sick and die from coronavirus, and they say they have also found a link to blood type, CNN reports.

Their findings, published Wednesday, June 17 in the New England Journal of Medicine, point to a possible explanation for why some people get so seriously ill with the virus, while most barely show any symptoms at all.

They found people with Type A blood have a higher risk of catching coronavirus and of developing severe symptoms, while people with Type O blood have a lower risk.

"Our genetic data confirm that blood group O is associated with a risk of acquiring Covid-19 that was lower than that in non-O blood groups, whereas blood group A was associated with a higher risk than non-A blood groups," the researchers wrote in their report. They found people with Type A blood had a 45% higher risk of becoming infected than people with other blood types, and people with Type O blood were just 65% as likely to become infected as people with other blood types.

The large international team first published their findings on a non-peer-reviewed preprint server. The report has now been reviewed and published in the widely respected journal.