Corona test: Some people seem to have immunity to Sars-CoV-2.Image: KEYSTONE
Even after more than three years of Corona, it is still not entirely clear why some people become infected with the virus – and others don’t.
Melanie Rannow / t-online
An article by
There are still numerous people who have never knowingly been infected with the coronavirus. And this despite contact with infected people. Why is that?
First of all: There is no one definitive answer that explains non-infections. Rather, the key may lie in a combination of different circumstances. Scientists assume that some people are more contagious than others, which may depend on their viral load and their symptoms.
Several studies indicate that genes play a crucial role here.
Study: Gene variant could protect against corona symptoms
Researchers from the USA and Australia have found an explanation for why some people only become infected with Corona asymptomatically – i.e. without any noticeable symptoms. They suspect that these people have a special variant of the genes, so-called HLA molecules.
According to the scientists, these can help the “killer T cells” to recognize the coronavirus even if the immune system has never had contact with the virus before and to fight it more quickly.
It has long been suspected that some HLA variants protect their carriers from certain pathogens. In Europe, around eight percent carry this gene variant.
That’s why some people are spared from Corona
In addition to genes, the immune system also has a significant influence on whether you are more susceptible to an infection or not. Researchers at Imperial College in London found that a high proportion of specialized T helper cells in the immune system, which were formed as a result of an infection with other corona cold viruses, can contribute to protection against the Sars-CoV-2 coronavirus.
What are T helper cells?
T helper cells are lymphocytes and play an important role in the immune system. Their proportion can be measured in the blood. They can recognize and kill the body’s own cells that have been infected by viruses.
One explanation as to why some people have never had Corona could be the existing Corona cold viruses that are circulating worldwide and had already infected millions of people before the pandemic.
Blood groups also apparently influence both the transmission of the virus and the course and severity of the disease.
Protection through vaccinations is often underestimated
Vaccination protection is probably often underestimated: the levels of antibodies in the blood, which can render coronaviruses that penetrate the body harmless, decrease in the time after vaccination.
However, the protection – especially the Corona booster – remains for a few months and can protect against infection.
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