Study refutes theory that blood type affects COVID risk

A or B, AB or O, it does not matter – your blood type has nothing to do with your risk of developing severe COVID-19, according to a new study.

Early in the pandemic, some reports suggested that people with A-type blood were more susceptible to COVID, while those with O-type blood were less.

But a survey of nearly 108,000 patients in a three-state health network found no link between blood type and COVID risk.

“Since the beginning of this pandemic, there has been a link between blood type and susceptible diseases,” said Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Safety, said.

“From this large study, it appears that there is no link between blood type and susceptibility or severity, and that other explanations were probably present,” adds Adalja, who had no role in the study.

An early report from China suggested that blood type could affect COVID risk. Later studies from Italy and Spain support this, researchers said in background notes.

However, other studies from Denmark and the United States have yielded mixed and conflicting results.

To clarify matters, researchers led by Dr. Jeffrey Anderson of the Intermountain Medical Center Heart Institute in Murray, Utah, analyzed data from tens of thousands of patients with Intermountain Healthcare, a nonprofit health system of 24 hospitals and 215 clinics in Utah , Idaho. and Nevada.

Of those in the analysis, nearly 11,500 tested positive for coronavirus, while the rest were negative.

Blood type did not play a significant role in the risk of someone contracting COVID, the researchers reported on April 5. JAMA Network open.

“I have always said that this whole affair with the blood groups is a lot of hope over nothing,” said Dr. Aaron Glatt, chair of the Department of Medicine and Hospital Epidemiologist at Mount Sinai South Nassau in Oceanside, NY, said. “It was never an important enough thing that people should be afraid if they have one type of blood group or can be reassured if they have another blood type. It never made a practical difference.”

Glatt was not involved in the new research.

He said that the findings of earlier studies show why correlation is not the same as cause – in other words, to show that two things are statistically linked is not the same as to prove that one caused the other.

“If you look at enough things, you’ll find some random findings that may or may not be relevant,” Glatt said. “Some people looked at so many different variables and one of them was blood type. They saw that some people did worse with a certain blood type, but the studies were contradictory, which makes sense if it’s random.”

Glatt concluded: “It brings this whole thing to rest, but it should never have started.”

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