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. Over the past few months, several research studies have hypothesized that the blood type has an impact on the risk of contracting the virus as well as 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.
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 found 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 supplemental 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.
This is lower than the prevalence of type O in a population of 2.2 million Danes, 41.7%, so the researchers determined that people with type O had avoided infection disproportionately. ” 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 of other blood groups. An April study also (although it has not yet been peer reviewed) found that among 1,559 coronavirus patients in New York City, a lower proportion than expected had type O blood.
And in March, a study of more than 2,100 coronavirus patients in the Chinese cities of Wuhan and Shenzhen also found that type O people had a lower risk of infection. Previous research has also suggested that people with Type O are less susceptible to SARS, which shares 80% of its genetic code with the new coronavirus. A 2005 study in Hong Kong found that most people with SARS had non-O blood types.