Home Mozambique Exposure to Harmless Coronaviruses Boosts Immunity to Covid: Study

Exposure to Harmless Coronaviruses Boosts Immunity to Covid: Study

LONDON: Immune responses to other human coronaviruses, most of which only cause harmless colds, may provide some protection against SARS-CoV-2 (Covid-19), according to new research published in the journal ” Nature Communications ”.
It is known that infections with the new coronavirus, which causes Covid-19, and vaccination lead to strong antibody responses against SARS-CoV-2.
This week, researchers at the University of Zurich (UZH) revealed a cross-sectional immune response that experts believe could be an important piece of the puzzle of how to achieve full immunity against coronaviruses.
“People who have had strong immune responses to other human coronaviruses also have some protection against infection with SARS-CoV-2,” said Alexandra Trkola, director of the Institute of Medical Virology at the UZH.
“Our study shows that a strong antibody response to human coronaviruses increases the level of antibodies against SARS-CoV-2. Thus, a person who has acquired immunity against harmless coronaviruses is therefore also better protected against serious infections with the virus. SARS-CoV-2, “she said. noted.
In the study, the researchers used a specially developed test to analyze the levels of antibodies against four other human coronaviruses in 825 serum samples taken before the emergence of SARS-CoV-2.
They also examined 389 samples from donors infected with SARS-CoV-2.
Combining these analyzes with computer models allowed the team to accurately predict how well the antibodies would bind to and neutralize the invading viruses.
Researchers were able to show that people who caught SARS-CoV-2 had lower levels of antibodies to the coronaviruses that cause common colds than people without the infection.
Additionally, people with high levels of antibodies to harmless coronaviruses were less likely to have been hospitalized after contracting SARS-CoV-2.
This type of immune response is called cross-reactivity and also occurs with T cell responses, the immune system’s additional line in defense against infection.
People are not fully protected against SARS-CoV-2 until soon after recovering from an infection or receiving an effective vaccination.
This is when the antibody levels against the virus are still very high.
As these levels drop, infection is no longer prevented, but immunological memory quickly reactivates the body’s defenses, the production of antibodies as well as the defense of T cells.
“Of course, the immune responses targeting SARS-CoV-2 that are mounted by memory cells are much more efficient than the cross responses. But even if the protection is not absolute, the cross immune responses shorten the infection and reduce its severity.
And that is exactly what is also achieved through vaccination, just much, much more effectively, ”added Trkola.
According to UZH, it is not yet clear whether this cross-reactivity also works in the opposite direction.
It remains to be seen whether immunity against SARS-CoV-2 – achieved through vaccination, for example – also offers protection against other human coronaviruses.
“If immunity against SARS-CoV-2 also provides some degree of protection against infection with other coronaviruses, we would be an important step towards achieving full protection against other coronaviruses, including any new variant ”, explains the virologist.
This idea is also supported by the fact that the cross-reactive protection is not only based on antibodies, but most likely also on T cells.
The study was funded by the University of Zurich’s Pandemic Fund, the Swiss Red Cross, the University Hospital of Zurich, the Swiss National Science Foundation and Gilead.

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