Will there ever be a different blood type

Researchers are divided on the influence of blood type on Covid-19 disease

In a new study by Harvard Medical School, researchers assume that the blood type does not play a decisive role in Covid-19. For their study, the doctors analyzed the data of 1289 people who tested positive, almost 500 of those infected were treated in hospital.

The latest study sees no connection between blood type and Covid-19

You write in the journal "Annals of Hematology": The blood type is not associated with a severe worsening of symptoms in people who test positive for COVID-19. With this, the researchers contradict earlier studies that had found a possible connection between blood group A and a severe course of Covid-19.

However, the Harvard Medical study found that there are small differences for blood groups B and AB in patients with corona symptoms. They tested positive for COVID-19 slightly more often, while people with blood type O tested positive slightly less often. The rhesus factor also seems to play a certain role: there were slightly more people with rhesus-positive blood among those who tested positive.

However, the study authors themselves rightly note that the number of patients examined is relatively small.

Earlier studies see a higher risk of severe Covid-19 courses with blood group A.

Molecular biologists from Kiel University and an international team analyzed blood samples from over 1,600 patients in intensive care units in Italy and Spain. As a control group, they examined the blood samples from randomly selected men and women from the same countries. In doing so, they examined certain genetic characteristics.

By analyzing the genetic make-up, the researchers identified gene variants that are associated with a severe course of Covid-19. The gene on which a person's blood group depends is also located at these gene locations.

How did the different blood groups come about?

And it turned out that patients with blood group A had a particularly high risk of a serious course of the disease. The patients with blood group 0, on the other hand, were better protected. The scientists published their results in the New England Journal of Medicine.

Two other preprint studies from China and the USA had already come to similar results.

There are various diseases that progress differently depending on the blood group

The connection between a person's blood group and certain diseases has been observed quite often. People with blood group 0 therefore develop cardiovascular diseases less often than other blood group types.

In the case of diabetes, people with blood group 0 also have the lowest risk of disease. The largest here has blood group B. Those with blood group AB rarely have high blood pressure.

The reasons for these relationships have not yet been clarified. However, these observations have so far been based solely on case-control studies, the results of which are prone to error.

Blood type is just one possible factor

If it turns out that there is a connection between the blood group and the severity of a possible Covid-19 disease, then the blood group is only one factor among several. The most important factor so far still seems to be previous illnesses. Other factors can be age and gender.