At the beginning of the pandemic, there were numerous studies showing that the blood group plays a decisive role in the risk of infection and the course of the disease in Covid-19. Now there is a new study from France, which – like many other studies – comes to the conclusion that people with blood group 0 are much less likely to be infected with the corona virus. At the same time, according to the conclusion of the new research, people with blood group 0 are particularly good at passing the virus on to others and are therefore so-called “superspreaders”.
The results of Study from France published in the journal “frontiers in Microbiology”. also seem plausible for the scientist Andre Franke from the University of Kiel. He already had in June 2020 a much-noticed study published on the connection between blood groups and corona infections. However, Jacques Le Pendu, head of the work that has now been published, warns in the BR interview: The blood group alone does not protect against a corona infection, certainly not against one with the omicron variant.
Crucial in case of transmission – compatibility of blood group
For their study, the team led by Jacques Le Pendu from the Université de Nantes interviewed more than 300 close-knit couples, one of whom was infected with the corona virus. The aim of the study was to find out how often the other partner had been infected and what blood groups the people had.
The result was that people whose blood groups would not get along in the event of a transfusion were much less likely to be infected by their partner than those whose blood group was “compatible” with their partner, as researchers call the compatibility of blood groups with one another. According to research leader Le Pendu, the risk of infection was “more than 40 percent lower”. Why that also means that people with blood group 0 have the lowest risk of being infected with the coronavirus is actually quite simple: after all, blood group 0 is only compatible with your own.
Digression: why blood groups do not get along
The reason why the different blood groups “do not get along” are small proteins on the red blood cells, so-called antigens. The blood of blood group A has corresponding A antigens, B has B antigens. Group 0 blood has no antigens at all, but has antibodies against A and B, which attack the cells. If people with blood group O were given blood of blood group A, B or AB in a blood transfusion, their blood would clot, which would be life-threatening.
Why people with blood group 0 are less at risk
According to the findings of the researchers led by Le Pendu, it is precisely this antibody defense that could also be the reason why people with blood group 0 are particularly well protected against coronavirus infection. Namely, when the corona virus “itself incorporates the blood group antigens into its surface”, which Le Pendus believes could be the case.
People with blood group 0 could therefore – thanks to their antibodies against A and B – fight corona viruses particularly well – at least if they come from people with a different blood group. After Statistics of the German Red Cross Just over 40 percent of the population in Germany have blood group 0.
Blood group 0: Low risk of infection, but super spreader
And yet blood group 0 has a disadvantage with regard to the corona pandemic, according to the French researchers in their study. Since blood type 0 blood has no antigens on the surface of the blood cells, people with blood type 0 can become superspreaders particularly often. The virus they pass on does not have matching antigens. Despite the presence of antibodies, it can multiply unhindered and cause disease.
Andre Franke, a microbiologist from the University of Kiel, is also convinced that this is the case. “These viruses fly under the radar, which means that if these viruses meet a person who has antibodies against A and B, these viruses cannot be recognized so well,” he explains in the BR interview.
Infection with corona depends on genes, immune system and vaccination status
But according to experts, not only the blood group determines the risk of infection with SARS-CoV-2. Genes, the immune system and last but not least the vaccination status also play a role. For example, the genetic information for a receptor on the cells of some people is slightly altered, making it harder for corona viruses to penetrate. The following applies to the immune system: Anyone who has had to fight similar viruses before is better protected against infection.
And the vaccination status is also crucial, emphasizes the German researcher Andre Franke. Like the French, he did find a lower risk of infection in people with blood group 0 in his studies. However, the values were “at 20 percent relative protection”, not over 40 percent, as the data analysis by the French shows. And that shows, according to Franke, “how important the vaccination is to simply increase this relative protection significantly.”
French scientist Le Pendu also warns against relying on blood type protection for coronavirus infection: “I myself have blood type 0, and yet I caught omicron. So you should take the same precautions, regardless of the type Blood type.” He also points out that his and other studies have only examined protection against delta and older variants, but not against omicron.
According to the current state of knowledge, it is relatively likely that people with blood group 0 could also be somewhat better protected against omicron or future variants. But it hasn’t been scientifically proven yet.