the type of blood group would impact the risk of infection and the severity of symptoms

As the COVID-19 pandemic continues its work in many countries, scientists continue to study the virus, its dynamics and its effects on human physiology. In recent months, several studies have hypothesized that the blood type had an impact on the risk of contracting the virus and the severity of symptoms. Two new studies support these hypotheses by showing that people with type O and B blood groups are less likely to be infected and develop less severe symptoms than other blood groups.

Two studies published this week suggest that people with a type O blood group have a lower risk of contracting the coronavirus, as well as a reduced likelihood of becoming seriously ill if infected. One of the new studies specifically found that COVID-19 patients with type O or B blood spent less time in an intensive care unit than their type A or AB counterparts.

They were also less likely to require mechanical breathing and to suffer from kidney failure. These new findings echo similar findings regarding type O blood obtained in previous research, specifying certain hypotheses about blood type as a risk factor.

Blood groups O and B: less severe symptoms in case of infection

The two new studies were published in the journal Blood Advances. One examined 95 critically ill COVID-19 patients at hospitals in Vancouver, Canada, between February and April. They found that patients with type O or B blood spent an average of 4.5 days less in the intensive care unit than those with type A or AB blood.

The latter group spent, on average, 13.5 days in the intensive care unit. However, the researchers did not see a link between the blood group and the total length of hospital stay for each patient. However, they found that only 61% of patients with type O or B blood needed a ventilator, compared to 84% of type A or AB patients.

graphs severity symptoms blood groups
Graphs comparing the need for mechanical ventilators (left), the need for dialysis (center) and the length of hospital stay in intensive care (right) between groups A / AB (red) and O / B (blue). Credits: Ryan L. Hoiland et al. 2020

Type A or AB patients, on the other hand, were also more likely to need dialysis, a procedure that helps the kidneys filter toxins from the blood. ” Patients of these two blood groups may be at increased risk of organ dysfunction or damage from COVID-19 than people with blood group O or B Write the authors of the study.

Blood group O: lower risk of infection

A June study revealed a similar link: Patients in Italy and Spain with type O blood had a 50% reduced risk of severe coronavirus infection (meaning they needed intubation or supplementation oxygen) compared to patients of other blood groups.

The second study found that people with type O may have a lower risk of getting the coronavirus in the first place, compared to people with other blood groups. The team examined nearly half a million people in the Netherlands who were tested for COVID-19 between late February and late July. Of the approximately 4,600 people who tested positive and declared their blood type, 38.4% had type O blood.

risk infection coronavirus blood group type O
People with type O blood group show a much lower prevalence of infections with the SARS-CoV-2 coronavirus. Credits: Mike Bogetofte Barnkob et al. 2020

This is lower than the prevalence of type O in a population of 2.2 million Danes, 41.7%, so the researchers determined that type O people had disproportionately avoided infection. ” Blood group O is significantly associated with reduced sensitivity », Write the authors.

Results in line with previous research

In general, blood type depends on the presence or absence of proteins called A and B antigens on the surface of red blood cells – a genetic trait inherited from parents. People with type O blood do not have any of these antigens. It is the most common blood group: around 43% of French people have type O blood.

The new studies on the blood group and the risk of coronavirus align with previous research on the subject. A study published in July found that people with type O were less likely to test positive for COVID-19 than those with other blood groups. An April study also (although it has yet to be peer reviewed) found that among 1,559 coronavirus patients in New York City, a lower proportion of people than expected had type O blood.

And in March, a study involving more than 2,100 patients patients with coronavirus in the Chinese cities of Wuhan and Shenzhen also revealed that people with type O had a lower risk of infection. Previous research also suggested that type O people were less susceptible to SARS, which shares 80% of its genetic code with the new coronavirus. A 2005 study in Hong Kong found that most of those infected with SARS had non-O blood groups.

Sources : Blood Advances (1, 2)

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