This Blood Type Makes You More Likely to Catch COVID, New Study Says

Zachary Mack
·5 min read

By now, a year into the pandemic, most of us know that certain conditions or personal habits can affect our chances of catching coronavirus or developing severe COVID. But there is also mounting research that certain genetic traits that aren't always visible to the naked eye could also put you at higher risk of the disease. Now, a new study from scientists at Harvard Medical School and Emory University School of Medicine has found more evidence that blood type can play a factor in how likely you are to catch COVID overall. Read on to see how what's in your veins could increase your risk, and for more on what else could be increasing your chances of getting sick, see If You've Done This Recently, You’re 70 Percent More Likely to Get COVID.

The coronavirus is more likely to attach to a specific kind of type A blood cell.

The team of scientists at Harvard and Emory conducted a laboratory study to better understand how SARS-CoV-2 interacts with A, B, and O blood types. The researchers focused on the part of the virus known as the receptor binding domain (RBD), which the pathogen uses to attach to cells once it enters the body.

The results, which were published in the journal Blood Advances, showed that the virus was more likely to attach to type A cells, specifically the type of blood cells found lining the respiratory system. The virus showed no preference for cells from other blood types or respiratory cells from the B or O blood groups, as Live Science reports.

The study authors believe that their results can help explain why some people are more susceptible to COVID. "It is interesting that the viral RBD only really prefers the type of blood group A antigens that are on respiratory cells, which are presumably how the virus is entering most patients and infecting them," Sean Stowell, MD, one of the study's authors from Brigham and Women's Hospital in Boston, said in a statement.

Unfortunately, this might be a COVID risk factor that can't be controlled.

The study's authors pointed out that unlike other potentially high-risk conditions, nothing can be done to lessen the risk created by our genetic makeup. "Blood type is a challenge because it is inherited and not something we can change," Stowell said. "But if we can better understand how the virus interacts with blood groups in people, we may be able to find new medicines or methods of prevention," he added.

The study authors said the findings also raised even more questions that warranted further examination. "Does this really influence the ability of the virus to get into cells? Does it just influence its ability to adhere to the cells? That's open-ended," Stowell said. "We're working on that right now, but the jury is still out." And for more on how you can help improve your odds, check out These 3 Vitamins Could Save You From Severe COVID, Study Finds.

Previous research has shown people with type A blood are also more susceptible to severe COVID cases.

The recent research is far from the only study to consider different blood types and how they present different COVID risks. Other studies have recently found that blood type can affect susceptibility to COVID. In December, researchers from the GenOMICC Consortium, an international association of scientists that study the connections between severe illnesses and genes, compared the genes of more than 2,000 COVID-19 patients in the U.K. with those of healthy people, The Washington Post reports.

Initial research from the same team, published in the journal Nature in October, found that those with type A blood were more likely to develop serious illness when infected with the novel coronavirus. "Blood group A was associated with a higher risk than non-A blood groups," the authors wrote. And for more COVID news delivered right to your inbox, sign up for our daily newsletter.

Type O blood has been linked to a reduced COVID risk.

Conversely, a study published in the journal Annals of Internal Medicine in November found that your risk of catching COVID-19 is slashed if you have type O blood. The researchers behind the study at St. Michael's Hospital in Toronto, Canada, examined the COVID-19 test results of 225,556 Canadians between Jan. 15 and Jun. 30. They looked at both how likely a patient was to contract the virus, as well as how likely they were to become seriously ill or die as a result. They found that people with type O blood were 12 percent less likely to contract COVID-19 and their risk for severe COVID-19 or death was 13 percent lower, compared to those with A, AB, or B blood types.

The four main blood groups—A, AB, B, and O—can also be Rh-positive or Rh-negative. When the researchers looked at this second classification, they found that those with Rh-negative blood are also “somewhat protected” from the virus. "An Rh− status seemed protective against SARS-CoV-2 infection," the study authors wrote. Additionally, "Rh− had a lower [adjusted relative risk] of severe COVID-19 illness or death."

And if you're O-negative, which is very rare, you may be even further protected from COVID. "Rh− blood type was protective against SARS-CoV-2 infection, especially for those who were O-negative," the authors wrote. According to Reuters, study co-author, Joel Ray, MD, of St. Michael's Hospital, suggested that people with these more resistant blood types may have already developed antibodies that can recognize certain aspects of COVID-19 and are therefore better prepared to fight it off. And for more on how you could potentially keep yourself safe, check out This Common Medication Could Save You From Severe COVID, New Study Says.