People with all blood types are at risk for COVID-19.

Lots of people are talking about whether your blood group (A, B, AB, or O) raises or lowers your chance of coming down with COVID-19. This idea is based on one unpublished, unreviewed study from researchers in China, who tried to compare the blood groups of patients hospitalized with COVID-19 to the blood groups in healthy people.

  Figure description: You blood type, or blood group, is inherited from your parents. The blood groups are defined by different molecules on the surface of your red blood cells, as illustrated above. Image from    InvictaHOG/Wikimeida Commons   .
Figure description: You blood type, or blood group, is inherited from your parents. The blood groups are defined by different molecules on the surface of your red blood cells, as illustrated above. Image from InvictaHOG/Wikimeida Commons .

Unfortunately, there are problems with the study. To make a good comparison, the researchers should show that the healthy people and the sick people are otherwise similar. But actually the healthy people were part of different studies conducted 4 to 5 years earlier. There’s no way to know (based on the information the researchers provided at least) if the healthy people are the same as the people who are now sick in the hospital.

What if, for example, the healthy people lived in a different part of the city than where the outbreak occurred? Or if a bunch of people moved into and out of the city, and now the percentage of each blood type is different? Maybe there was a huge family reunion and everyone got COVID-19, and because they were all related, they had the same blood type! These possibilities make it impossible to know if the study’s conclusions are correct or not.

It’s an interesting idea that your blood group might affect your risk of getting sick, and in fact, blood groups do matter when it comes to your risk of getting a stomach bug called norovirus. But there's currently no solid scientific evidence that blood group matters for COVID-19.

What we do know is that the elderly and those with certain health issues (like asthma, other lung disease, heart problems, weak immune system, diabetes, kidney problems, and liver issues) are most at risk. But people of all ages can get sick and even die from the virus. So, whether you’re group A, B, AB, or O, practice the same precautions to avoid spreading the virus. 

Last reviewed: March 27, 2020 at 11:00 AM
Scientific review: JAB, ERS