How Does Coronavirus Affect Each Blood Group?

30 May, 2020
A scientific study in China looked at how the coronavirus affects each blood group. This is a single study, and the results should be taken with caution, as they aren't definitive. However, we'll talk about what they may mean in this article.

In China, a scientific study was carried out in March to analyze how the coronavirus affects each blood group. Basically, it was a statistical count of those infected according to their blood group antigens.

Based on those results, it was postulated that patients with COVID-19 who belonged to blood group A were more susceptible to infection. At the other extreme, those with group O became less infected.

However, the same researchers warn us that this data cannot be taken as definitive evidence to understand how the coronavirus affects each blood group. It would be wise to wait for more information to give a more definite verdict.

However, some specialists are saying that the results are not unreasonable. As we’ll discuss in this article, blood groups are known to be a part of the human immune system and have, therefore, certain links to viral diseases.

The Chinese research used samples from 2,173 participants, and they concluded that the proportion of patients infected by coronavirus with group A was higher than in the general population. In contrast, the proportion of infection of people in group 0 was significantly lower.

What are blood groups?

Blood groups are a human classification of proteins that are present in red blood cells. The classification system dates from 1901 and was devised by Karl Landsteiner, a biologist from Austria.

Landsteiner’s idea came about when he noticed that when transfusions were given, some were successful and others weren’t. The researcher hypothesized about the existence of some kind of tissue rejection and proceeded to investigate the causes. By mixing blood samples from different people in a laboratory, he observed that sometimes the blood joined together, and sometimes it didn’t and caused a reaction instead.

He hypothesized that this happened due to an immune response, and indeed it did. There are people with certain proteins that others don’t have in their red blood cells, and that’s where the incompatibility lies. Thus, blood groups were cataloged as A, B, O, or AB depending on whether one or several of these proteins are present in the blood.

Later on, the classification was complemented with the Rh system which scientists also call the D antigen system. Here, scientists also evaluate the presence of an antigen in the red blood cells, which may or may not be present.

People with the D antigen in their red blood cells are Rh-positive. If the antigen isn’t there, then they’re Rh-negative. This may be a problem for pregnant women, for example.

Red blood cells.
Blood groups are determined by whether or not certain proteins are present in red blood cells.

Read on: Coronavirus Reinfection: The Latest Findings

How does coronavirus infect us?

To determine if the coronavirus affects each blood group differently, it’s important to recognize that this virus enters cells is through proteins. SARS-CoV-2 has spicules on its surface, which act as entry keys.

We now know that the cells of the pulmonary alveoli, the renal cells, some cardiac cells, and neurons all have receptors for the coronavirus. The receptor in question is ACE2, which is part of the renin-angiotensin system.

Of course, the ACE2 receptor is not in the body waiting for the coronavirus. It exists for other reasons. The problem is that SARS-CoV-2 finds a nearly perfect fit there and eventually enters the cells.

While there is no record of the coronavirus infecting red blood cells, as we’ve discussed, the blood grouping system is linked to immunity. These proteins and antigens on the surface of red blood cells work to recognize external or distinct agents.

What if blood group A doesn’t have the same ability to detect the infection as blood group B? This, as we’ll now discuss, opens the door to further research.

Coronavirus virus.
The coronavirus enters the cells via the ACE2 receptors.

Find out more: How Coronavirus Infects Cells in the Lungs

Why does the coronavirus affect each blood group differently?

Overall, the coronavirus’s mechanism of entry into the cells is the reason why it affects each blood group differently. However, it’s important to remember that the results of this study are preliminary. Nevertheless, scientists believe that the link can be explained by immunology.

Some of the proteins we’re talking about here are sugars or bind to the sugars circulating in the blood. (Remember, we’re talking here about sugar as a chemical composition. It’s not the compound we use in our daily cooking!) Scientists have known for a long time that the coronavirus family has an affinity for sugar.

Regarding the red blood cells, the antigens that regulate the rejection or acceptance of other blood also use sugars. So, it isn’t unreasonable to think that a patient with certain sugars in their red blood cells will respond differently from a patient without them, for example.

Blood groups and coronaviruses

Overall, this information certainly won’t change the measures currently in place. However, it is an incentive to study the behavior of viruses in certain situations in the future. Perhaps with this knowledge, we’ll be able to unravel the problem a bit more. That way, we can improve our future response to external agents, such as the coronavirus.