New Large Scale Study Finds That Your Risk Of Contracting COVID-19 Reduces If You Have This Blood Type

A new large-scale study has found that a person’s risk of contracting the dreaded COVID-19 pandemic reduces if he or she has a particular blood type.

The study, published in the journal Annals of Internal Medicine, states that type O blood provides some protection against the deadly virus.

The researchers at St. Michael’s Hospital in Toronto, Canada, examined the test results of 225,556 Canadians who had been tested for COVID-19 between January 15 and June 30.

They looked at both how likely a patient was to contract COVID-19, and how likely they were to become seriously ill (or even die) from it if they did.

The results were notable: Adjusting for demographics and comorbidities, the risk for a COVID-19 diagnosis was 12 percent lower for people with type O blood and the risk for severe COVID-19 or death was 13 percent lower, compared to those with A, AB, or B blood types.

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Characteristically, type O blood has neither A nor B antigens in the red blood cells but has both A and B antibodies in the plasma.

Type O+ is the most common blood type which accounts for between 37 percent and 53 percent of people in different ethnic and racial groups.

Negative blood types are also somewhat protected from the virus

Those four main blood groups — A, AB, B, and O — can be Rh-positive or Rh-negative, meaning that there are eight blood groups in total.

When the researchers looked at this second classification, there was further good news — people in any blood group which is Rh-negative 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.”

Those who are O-negative may be the least likely to get COVID-19

If a patient was O-negative, they were particularly protected from the novel coronavirus, the authors noted. “Rh− blood type was protective against SARS-CoV-2 infection, especially for those who were O-negative,” they wrote.

Unfortunately, the O-negative is a much more rare blood type.

Previous research has found that people with A blood types are more at risk. For a March study out of the Southern University of Science and Technology in Shenzhen, China, scientists tracked the blood types of nearly 2,200 COVID-19 patients in Chinese hospitals, along with those of about 27,000 individuals who didn’t have COVID-19 in the same areas.

The results showed that those with A blood types were significantly more likely to contract the coronavirus compared with other blood types.

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O and Rh-negative blood types may already have COVID-19 antibodies

The new study’s co-author, Joel Ray, MD, of St. Michael’s Hospital, suggested that people with these more resistant blood types [O and Rh-negative blood types may already have COVID-19 antibodies] may have already developed antibodies that can recognise certain aspects of the novel coronavirus and are therefore better prepared to fight it off.

“Our next study will specifically look at such antibodies, and whether they explain the protective effect,” Ray said.