Are you protected against the new coronavirus as soon as you’ve become infected and survived the disease? The answer to this question is of immense importance to the course of the pandemic. Because only if a large part of the population gains immunity over time – be it through infection with the virus or through a vaccination – the infection process can subside. At least with regard to an infection with Sars-CoV-2, researchers are now cautiously hoping: According to the data of a recent study Most people could be immune for at least eight months after suffering from illness.
Jennifer M. Dan’s team from the La Jolla Institute for Immunology and the University of California in San Diego examined blood samples from more than 180 Covid-19 patients. Most of them experienced only mild symptoms, around seven percent had to be treated in hospital. 43 samples were submitted at a time when the infection had already been between six and eight months.
The researchers’ analyzes show that all types of immune cells they examined were still present in significant quantities in most of the participants eight months after infection. Antibodies, which the body produces to defend itself against the virus, decreased most significantly. However, T cells that kill infected cells showed only a slight decrease. B cells, which can form new antibodies in the worst case and function as immunological memory, increased in most of the test subjects.
Absolutely reliable statements cannot yet be made on the basis of this data. Because the processes that lead to immunity to Sars-CoV-2 are still not well understood. However, a plausible interpretation of the results is that around 95 percent of those infected build up a lasting immunological memory that at least protects against a severe course of Covid-19, the researchers write. Pointing in a similar direction a study published by Australian scientists at the end of December 2020 in the journal Science Immunology.
Dan and her colleagues point out, however, that immunity of this kind does not develop equally in all people: if a person produces fewer antibodies, T and B cells at the beginning of the infection, these differences are still present months later. Presumably it could be precisely those patients who then fall ill again.
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