WASHINGTON — Since the start of the coronavirus pandemic, scientists have tried to figure out who is most at risk and who is most likely to spread the infection. While those answers seem to vary month to month, a pair of studies find your blood type may play a key role in how badly COVID-19 affects you. The American Society of Hematology says people with blood type O have both a lower risk of infection and lower chance of severe complications from the virus.
According to a study published in Blood Advances, O-type blood may have some protection against COVID-19. Researchers in Denmark find fewer coronavirus patients have O blood compared to those with A, B, and AB blood.
According to the American Red Cross, O-positive is the most common type of blood across all races. People with O-blood are also capable of donating red blood cells to any other type. The Danish researchers suggest these universal donors are also at slightly lower risk of contracting COVID, based on their review of over 473,000 people tested for the virus. Their study matched these results against a control group 2.2 million people in the general population. The findings also reveal patients across different ethnic groups continue to show fewer infections if they have O blood.
“It is very important to consider the proper control group because blood type prevalence may vary considerably in different ethnic groups and different countries,” says study author Torben Barington, MD, of Odense University Hospital in a press release. “We have the advantage of a strong control group – Denmark is a small, ethnically homogenous country with a public health system and a central registry for lab data – so our control is population-based, giving our findings a strong foundation.”
Which blood types put coronavirus patients in danger?
While type O blood may provide small benefits during the pandemic, another study in Blood Advances finds patients with A and AB blood may see worse symptoms. Canadian researchers suggest those with A or AB blood are more likely to suffer lung damage due to COVID-19.
Study authors examined 95 critically ill coronavirus patients in Vancouver, Canada and found more people with A and AB blood had to be placed on ventilators. These patients also suffered other organ damage, with many needing dialysis for kidney failure.
While the average stay in a hospital was the same across all blood types, A and AB patients tended to spend longer periods in the intensive care unit compared to O and B blood COVID patients.
“The unique part of our study is our focus on the severity effect of blood type on COVID-19. We observed this lung and kidney damage, and in future studies, we will want to tease out the effect of blood group and COVID-19 on other vital organs,” study author Mypinder S. Sekhon, MD, from the University of British Columbia reports.