Several studies support the hypothesis that blood groups have an impact on Covid-19 contamination. Group O would be more protective.
What if your blood type protected you against Covid-19?
This is what Inserm researchers are saying in a study published in the journal Viruses at the end of January. It confirms around forty other studies on the subject carried out around the world since March 2020.
« A general consensus is emerging in which group O blood is associated with a lower risk of contracting Covid-19, » the document argues.
The risk of infection is between 10% and 33% lower for people with this blood type. The figure varies by country but does not differ by age or sex.
« O’S ARE LESS CONTAMINATED BY A’S AND B’S »
Covid-19 is transmitted from person to person and upon arriving in a healthy body, it is marked by the blood of the previous host.
Groups O naturally develop antibodies against groups A and groups B (which is why they are universal donors), so when the virus arrives from a person of one of these groups, it would be partially blocked by this natural barrier. « The O’s are therefore less contaminated by the A’s and the B’s » , suggests Professor Le Pendu.
This would partly explain the slower rate of spread of the epidemic in certain countries where the distribution of blood groups is balanced (as in South Korea), or, on the contrary, fast in those where a particular group is largely in the majority (such as in Brazil).
Another hypothesis put forward to explain this less infection as well as fewer serious forms: the blood clots less in people in group O.
They are less prone to have cardiovascular problems or thromboses, which are aggravating factors against the coronavirus.
NOT A GUARANTEE OF IMMUNITY
The study was conducted before the exponential growth of the variants. Data are therefore lacking on this point. But if the « mechanism [of the variants] is the same » as the original strain, then the hypothesis « could also apply to the variants » , advances Jacques Le Pendu.
If the people of group O seem, because this is only a hypothesis still, more protected, it is not for all that a guarantee of immunity against Covid-19.
Already because in the best of cases, it would « only » reduce the risk of infection by 33%, but above all because the O’s contaminate each other, without any barrier this time, and contaminate all the others.