Genes, blood type or just luck? Why do some people get corona after close contact with infected people, and others do not?
The study is controversial, but its results are still interesting: after British researchers instilled the original variant of the Corona virus into the noses of 34 volunteers, more than half of them became ill. Although the amount of virus was small, it was the same for all participants.
There are many assumptions about why some become infected faster than others, regardless of vaccination. The explanation is often simple, however, and some people’s immune system fights off the virus so quickly after contact with an infected person that antigen tests don’t work, immunologist Martina Prelog explained to Deutschlandfunk Nova.
Another possible explanation: people who don’t seem to be infected have been infected before, but without realizing it.
In addition, other factors independent of vaccination are currently under discussion:
When the immune system is infected with a virus, it reacts to certain surface proteins from the foreign pathogen. If the virus is still unknown, the reaction often takes longer.
However, if the body becomes infected again, the immune system can react more quickly – because the previous infection was stored in the immune memory. The immune system can benefit even if it has fought similar or related viruses before. Then virologists talk about cross immunity.
According to a study by researchers from the University of Münster, this could also be the case with Covid-19. If participants have already contracted one of the four coronaviruses, they tend to follow a milder course. However, the omicron variant, currently prevalent in Germany, was not present during the observation period.
Researchers from Sweden came to a similar conclusion: in their previously published study, they came to the conclusion that previous infection with the virus that causes swine flu can also help the immune system with Covid19 infection. However, the team also hypothesizes that this protection is lower with the Omicron variant than with the original variant.
For some diseases, such as malaria, it is already known that some genetic mutations protect against disease better than others. In the case of HIV infection, tuberculosis or influenza, for example, certain genetic variants can help determine the severity of the disease course.
Such studies have already been conducted in connection with Covid-19. The DNA of people who had different degrees of symptoms after infection were compared. Several genes have so far been observed in people with particularly severe cycles. In a recent study, researchers found a relationship between eight genetic characteristics and the risk of corona infection.
Stimulating certain blood groups for infection is not a new idea in and of itself. Researchers have already come to the conclusion in studies conducted on other types of coronaviruses that people with blood type 0 get sick less often than people with other blood types.
Regarding Covid-19 as well, many researchers agree that the risk of infection tends to be lower in people with blood type 0. However, the effect appears to be very small.
However, there is currently no scientific consensus on which blood group carries the highest risk.
However, not only your blood type plays an important role. An affected person’s blood type also affects how likely they are to be infected.
In contrast to compatible blood groups, the risk of developing incompatible blood groups was 40 percent lower in the studies. This means that the risk of infection varies for individuals depending on how the blood groups are distributed in the population.
However, it is still not clear to what extent genetic factors influence in general. It is still difficult to generalize the results of the study.
However, the researchers hope that the results will help in the development of new drugs and treatment approaches.