Corona: Why a cold can currently even be helpful

Apparently there is a close connection between the coronaviruses, which cause coughs, runny nose and hoarseness, and SARS-CoV-2. An infection with the harmless seasonal known corona viruses should at least temporarily protect against Covid-19. This has been known for a long time. A Swiss team of scientists has now found new evidence for cross-reactive antibodies.

Classic pathogens

SARS-CoV-2 is not the only coronavirus that occurs in humans. Four similar viruses – OC43, HKU1, NL63 and 229E – are classic causative agents of seasonal colds.

“Children in the first years of life are particularly affected. Later, an immunity sets in that protects adults from diseases that may be more severe for them,” wrote the German Medical journal to the scientific results. The corresponding study by Zurich scientist Alexandra Trkola was in a few days ago Nature Communications appeared.

Specially developed test

The study examined the influence of immunity against the “old” coronaviruses on the risk of infection from SARS-CoV-2 and the risk of disease from Covid-19.

The team of authors from the University of Zurich used a specially developed test to examine the amount of different antibodies against the long-known seasonal coronaviruses found in humans in the serum of 825 blood donors from the time before the occurrence of SARS-CoV-2. They were compared with 389 samples from donors who were infected with Covid-19.

Hospitalized less often

“The researchers were able to show that people who were infected with SARS-CoV-2 had lower levels of antibodies against the common cold coronavirus. In addition, SARS-CoV-2 infected people with high antibody levels against the harmless coronavirus had to be hospitalized less often it said in a broadcast from the Swiss university.

Study author Trkola commented on the results as follows: “According to our results, a stronger antibody reaction against human coronaviruses also leads to higher amounts of antibodies against SARS-CoV-2. A person who has immunity against harmless coronaviruses is therefore also better off from severe courses of SARS -CoV-2 infections protected. “

What still needs to be clarified

It remains to be seen whether this cross-reactivity also works the other way round. So whether an immunity to SARS-CoV-2 – for example through a vaccination – protects against other human coronaviruses. “If SARS-CoV-2 immunity also offers a certain protection against infection from other coronaviruses, we would come a big step closer to comprehensive protection against coronaviruses, including newly emerging variants,” the Zurich virologist was quoted as saying by her university.

In any case, this assumption is supported by the fact that a cross-reactive protective effect is not only based on antibodies, but very likely also on T cells.

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