Type O blood less likely to contract COVID

FLORIDA — Research from genetic testing giant 23andMe found that differences in a gene that influences a person’s blood type can affect a person’s susceptibility to COVID-19, according to a report in

Bloomberg.

Scientists have been looking at genetic factors to try to determine why some people who contract the new coronavirus experience no symptoms, while others become gravely ill.

The company shared in a blog post this week that preliminary results from its ongoing genetic study of COVID-19—which currently has more than 750,000 participants— “suggest that O blood type appears to be protective.”

Specifically, people with type O blood were up to 18 percent less likely to test positive for COVID-19 than those of other blood types.

The results were still significant when researchers adjusted for factors like age, sex, body mass index, ethnicity, and other health conditions.

That said, the study has not yet been peer-reviewed and published in a scientific journal.

But this isn’t the first time researchers have identified a blood type link. Preliminary results from a study of 2,173 coronavirus patients in China found that people with type O blood had a lower risk of contracting COVID-19, while people with type A and type AB faced a higher risk. In April, researchers from Columbia University also published preliminary data that came to similar conclusions: people with type O blood were less likely to test positive for COVID-19 and those with type A blood were 33 percent more likely to test positive for COVID-19.

Wait, can blood type really impact your COVID-19 risk? It’s totally unclear at this point. When you look at the data that’s been collected so far, “the difference from a practical point of view is not very large between the blood types,” says Dr. William Schaffner, an infectious disease specialist at the Vanderbilt University School of Medicine.

An example: only 233 people out of 478 with type A blood tested positive for COVID-19 in the Columbia University study (48 percent), while 312 of 761 with type O blood (or 40 percent) also tested positive. Plus, the idea that your blood type may dictate your infectious disease risk isn’t completely new, explains infectious disease expert Amesh Adalja, M.D., senior scholar at the Johns Hopkins Center for Health Security.