The study provides further evidence that blood type (also known as blood type) may play a role in a person’s susceptibility to infection and his chance of having a severe attack of the disease. The reasons for this relationship are not clear and more research is needed to say what consequences, if any, there are for patients.
A Danish study found that among 473,654 people who were tested for Covid-19, only 38.4% with blood type O were positive – although among a group of 2.2 million people who were not tested, this blood type group makes up 41.7% of the population.
In another study, researchers from Canada found that among 95 patients critically ill with Covid-19, a higher proportion of blood type A or AB ̵
The Canadian study also found that those with blood type A or AB had a longer stay in the intensive care unit, a median of 13.5 days, than those with blood type O or B, who had a median of nine days.
“As a clinician … it’s at the bottom of my mind when I look at patients and stratify them. But in terms of the final marker, we need repetitive findings in many jurisdictions that show the same thing,” Dr. Mypinder said. Sekhon, a resuscitation doctor at Vancouver General Hospital and author of the Canadian study.
“I don’t think this replaces other risk factors for severity such as age and comorbidities, etc.,” added Sekhon, who is also a clinical assistant in the Department of Critical Care Medicine and the Medical Department at British Columbia University.
“If someone is blood type A, you don’t have to start panicking. And if you’re blood type O, you can’t go to pubs and bars.”
No need to worry
This is a very small difference in most people’s daily lives, unless a blood transfusion is needed. Nor should people worry unnecessarily about the link between blood type and Covid-19, said Dr. Thorben Barrington, a senior author of the Danish article and a clinical professor at Odense University Hospital in southern Denmark.
“We don’t know if this is some kind of protection for group O, or if it’s some kind of vulnerability in the other blood groups,” he said.
“I think it’s of scientific interest, and once we understand what the mechanism is, we may be able to use it proactively in some way in terms of treatment.”
In the Danish study, researchers analyzed data on Danish individuals who were tested between February 27 and July 30, and the distribution of blood groups among these people was compared with data from people who were not tested. They found that blood type was not a risk factor for hospitalization or death from Covid-19.
Both studies were published in the journal Blood Advances.
Although there are several theories, researchers still do not know what mechanism could explain the relationship between different blood types and Covid-19.
Sekhon said this could be explained by people with blood type O, who have less of a key clotting factor, making them less prone to blood clotting problems. Coagulation is a major driver of Covid-19 gravity.
Other possible explanations include blood group antigens and how they affect the production of antibodies that fight infection. Or it may be linked to genes linked to blood groups and their effect on receptors in the immune system.
“This is a repeated, interesting scientific observation that really requires further mechanistic work,” he said.
“Important research question”
The findings of the two new studies provide “closer evidence that blood type may play a role in a person’s susceptibility to Covid infection and his chance of having a severe attack of Covid-19,” said Dr. Amesh Adalya, a senior scientist. at the Johns Hopkins University Center for Health Security in Baltimore, which is not involved in any of the studies.
The previous genetic study, combined with the two new studies in Blood Advances, “suggests that this is a real phenomenon that we are seeing,” said Adalia, whose work focuses on emerging infectious diseases.
“Although we’re not quite up to the point where it’s iron, it’s obviously impressive and we haven’t seen anything out of place. The same pattern appears in the O blood type, which tends to be the one that stands out.” I told Adal.
Adalya said that blood groups and their susceptibility to various infections have been studied in the medical literature before. For example, studies show that people with blood type O appear to be more susceptible to norovirus infection.
As for the new coronavirus that causes Covid-19, “We need to understand the mechanism and understand it at the molecular level so that we can say for sure how this happens – that it’s really blood type O, not something like that. type tracks with O blood type, “Adalya said.
“We’re starting to see enough now that I think it’s an important research question that needs to be answered,” he said. “There is more science here, but it seems to me that there is more accumulation of evidence for this hypothesis.”