Studies: Blood type might predict your COVID risk

There are two new studies that show people with certain blood types could be at a lower risk of contracting COVID-19 or more likely to become seriously ill with the disease.

But Connecticut health experts question if the information is useful and hoped the research doesn’t deter anyone from taking basic health precautions.

“It’s interesting to know, but there’s not a whole lot you can do about it,” said Dr. Henry Yoon, medical director of Sacred Heart University’s physician assistant program and an associate clinical professor. “You can’t change your blood type.”

Dr. Michael Parry, chief of infectious disease at Stamford Hospital, said it’s an “interesting observation,” but pointed out that being at lower risk doesn’t mean people with certain blood types are immune to COVID.

“You’re still at risk,” Parry said. “It’s just a relative difference.”

The two studies were published this month in the journal Blood Advances, showing the impact of blood type on a person’s risk for COVID-19.

In one, researchers compared data from a Danish health registry for 473,654 people tested for COVID, and found that those with Type O blood were less likely to be infected than those with A, B, or AB type blood. There was no significant change in infection rate found among those with A, B and AB type blood.

The other study showed that COVID-19 patients with blood group A or AB are at a higher risk of requiring mechanical ventilation and “appear to exhibit a greater disease severity” than those with blood group O or B.

The study examined 95 COVID-19 patients in Vancouver, Canada, and found that, of the 57 patients with Type O or B blood, 61 percent required ventilation, compared with 84 percent of the 38 Type A and AB patients. Researchers also found that those with Type A and AB blood typically had longer hospital stays.

Yoon, who is also director of the family medicine residency program at Stamford Health, said studies such as these are helpful in understanding how COVID-19 works. However, he questioned how they can help protect anyone from COVID-19. One possible benefit, Yoon said, is that the studies might encourage people who aren’t Type O to be more cautious.

“Now if people say, ‘I’m not as safe as Type O, so I better pay more attention to mitigation strategies,’ that’s a bonus,” Yoon said.

But, on the other hand, he said, he hopes the research doesn’t encourage those with more “protected” blood types to be more foolhardy when it comes to mask-wearing and other safety precautions.

“We don’t want people saying, ‘I’m blood Type O, so I’m safer,’ ” Yoon said.

Parry said that while the study findings are compelling as science, they don’t change the fact that everyone, no matter the blood type, needs to continue protecting themselves from COVID and following safety guidelines.

“I think everyone needs to be careful and exhibiting same behaviors of maskwearing, social distancing and hand washing,” he said.

Kim Brent / The Enterprise New studies show people with Type O blood might be less likely to catch COVID-19, while those with A or AB could become seriously ill.