The blood group influences the risk of infection – healing practice

Blood group and risk of corona disease

The individual risk of coronavirus infection can vary significantly. But why do some people get infected with the novel pathogen – and others not? The blood group could play a role here, as researchers are now reporting.

As the Federal Center for Health Education (BZgA) wrote months ago on its portal “infektionsschutz.de”, several studies indicate that the blood group can influence both the personal risk of infection and the severity of the symptoms of COVID-19. However, these scientific studies have not shown consistent results. Researchers from Austria are now reporting on new findings.

Comparable studies confirmed

Scientists from the Medical University (Med Uni) Graz are currently investigating the possible connection between different blood groups and the likelihood of a COVID-19 infection at the University Clinic for Blood Group Serology and Transfusion Medicine. According to a press release, initial research confirms comparable studies from China and Europe, according to which people with blood group 0 are less likely to contract COVID-19 than people with blood groups A, B or AB. Now the mechanism on which this observation is based is to be investigated.

Causes that favor infection

Research is currently being carried out around the world into the causes that favor an infection with SARS-CoV-2 or influence the course of COVID-19. The AB0 blood group seems to play a role here, as study results from China and some European countries show. The red blood cells (erythrocytes) are ring-shaped cells that carry oxygen and carbon dioxide through the bloodstream. As explained in the communication, the “shell” of the red blood cells is called the “membrane”. In this membrane there are several different carbohydrates (sugar) and proteins that give the red blood cells a certain surface structure, they are also called “antigens”.

The “blood group carbohydrates” A and B are also such antigens. For the AB0 blood group, a distinction is made between the properties A, B, AB and 0 (zero). According to experts, people with blood group “0” do not have any of these blood group antigens on the surface of their red blood cells. In people with the blood group “AB”, both carbohydrates (A and B) are contained in the erythrocyte membrane. And with blood group “A” only the antigen “A” is present, with blood group “B” only the antigen “B”.

Retrospective case-control study

It is known that the sugar structures, as they are in the AB0 blood group system on the cell surface of the red blood cells, but also in the tissues of the respiratory organs and the gastrointestinal tract, not only in the blood group recognition of antibodies, but also in the recognition of microorganisms play a role. “Pathogens such as bacteria or viruses can selectively bind to blood group structures and influence the colonization of the affected tissue or the uptake in the cells,” explains Eva Maria Matzhold, the head of the study, molecular biologist at the University Clinic for Blood Group Serology and Transfusion Medicine, Med Uni Graz. “In our study, we are investigating whether ABO blood group properties can represent a possible further risk factor for infection and COVID-19 disease,” adds transfusion specialist Thomas Wagner.

In the first presented research results it could already be shown that a connection between the blood group and an infection with the coronavirus SARS-CoV-2 can be proven. This means that early indications from a study from China and from a genome-wide association study (European GWAS COVID-19 research group) can be confirmed. The study at Med Uni Graz is set up as a retrospective case-control study with a total of 399 SARS-CoV-2 positive people who were inpatient treatment due to COVID-19.

The severity of the disease remains unaffected

“Our study results show that people with blood group O have a statistically significantly lower probability of contracting COVID-19 than people with other ABO phenotypes (blood group A, B or AB),” the researchers report. Blood group AB, on the other hand, was found significantly more frequently in infected and COVID-19 patients compared to the frequency of occurrence in the healthy control group.

However, the severity of the COVID-19 disease remains unaffected by the AB0 blood group. This means that the disease is no easier in people with blood group 0 than in people with blood group AB. An AB0 blood group determination should currently not be used as a prognostic marker for the course of COVID-19. According to the researchers, the task now is to carefully research the mechanism that plays a role in this. Other blood group systems are also included in the investigations, explain the scientists. (ad)