According to a Chinese study, people with blood group O are better immunized against Covid-19 than people of other groups. But why?
We know that certain factors – such as age, cardiovascular and respiratory diseases, diabetes or obesity – increase the risk of mortality for people infected with the SARS coronavirus. -CoV-2. But there could be others. According to a recent Chinese study, for example, our blood type could have a significant impact on our susceptibility to Covid-19. What is it exactly?
Blood groups define categories of individuals according to the variety of antigens and antibodies present on red blood cells. There are three types of antigens (A, B and AB), and four blood groups (A, B, AB and O).
– Group A subject exhibits antigen A and anti-B antibodies.
– A group B subject has the B antigen and anti-A antibodies.
– A group AB subject has both A and B antigens and does not have anti-A or anti-B antibodies.
– A group O subject has no A or B antigen and has anti-A and anti-B antibodies.
That being said, a team of Chinese researchers recently investigated whether we could determine a relationship between blood type and the health status of patients with the SARS-coronavirus. CoV-2.
As part of this work, the researchers studied the blood types of 2,100 infected people in three hospitals in Wuhan and Shenzhen, 10% of whom had died. He then compared them to those of 3,694 Wuhan residents not infected with the virus.
Result, the distribution of blood groups among the 3,694 healthy residents in Wuhan was 32.16% for group A, 24.90% for group B, 9, 10% for group AB and 33.84% for group O. For patients with the disease, the ratios were:37.75% for group A, 26.42% for B, 10.03 % for AB and 25.80% for group 0.
In other words, it emerged from this study that people in group 0 had a 33% lower risk of infection . On the other hand, group A people seem to have a 20% additional risk of being infected (the ratios were essentially the same for the other groups).
So, at least for this sample, blood type seems to make a difference. Asked about the subject, Pr. Jacques Le Pendu, research director at Inserm, said to himself "not at all surprised by the results of this study.
It should be noted that similar differences in sensitivity between blood groups were also noted during the SARS epidemic in 2003. Pr. Le Pendu himself had was even at the origin of a study, published in 2008, aimed at explaining the causes of the observed phenomenon. And the answer, it seems, lies in antibodies.
People with blood group O have, as we recall, Anti A and Anti B antibodies, which constitutes a double defense compared to those of group A (with only one type of anti B antibody) or those of group B (anti A antibody).
In other words, these people would be better equipped to destroy the virus. These antibodies, more specifically, would be able to more easily block the interactions between the S protein of the virus and its cellular receptor, enzyme 2, thus preventing the pathogen from multiplying.
This partial protection mechanism would indeed have an impact on the spread of the disease:"We had done modeling work which showed that it slowed the spread very slightly “, emphasizes the researcher.
The problem is that over time, some people with type O lose a large part of their anti-A and anti-B antibodies. In an attempt to curb the spread of the epidemic, we might then consider "boosting" their defenses.
“We could do this through microbiota bacteria, which allow children to build their own antibodies, which we could administer in the form of probiotics , explains the researcher. This is all just theory... But it would be worth a try. This could be a complementary means to containment measures “.
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