Children and adolescents are much less likely to be infected with SARS-Cov-2 and are also considerably less contagious themselves. It has already been proven that immunity is fairly widespread in adults thanks to previous infections with the corona cold virus. Previous studies have one T cell immunity Antibodies neutralizing against SARS-Cov-2 have now been found in 60 percent of children between the ages of 6 and 16 years. In contrast, the proportion was only 6 to 10 percent in adults.
The new findings, which took place on Preprint-Server bioRxiv published explain a lot of the previously unclear developments. For example, the low risk of infection in children. But also the thesis of the accessibility of the Herdenimmunitätif 10 to 20 percent of the population has been infected with the new corona virus, this will further harden.
The infection appears to affect people who have not received immunity from T cells or antibodies from coronary cold virus disease. Taken together, herd immunity is 60 to 70 percent or more. This brings the spread of the virus to a standstill, similar to a vaccination.
The results of the study
Several related human coronaviruses (HCoVs) are endemic to the human population and cause mild respiratory infections. Using various tests to detect antibodies that react with the SARS-CoV-2 spike (S) glycoprotein, the London researchers are showing the presence of pre-existing immunity against the new corona virus in non-infected and unexposed people. SARS-CoV-2 S-reactive antibodies were easily detectable by a sensitive method in SARS-CoV-2-non-infected persons and particularly common in children and adolescents.
The outer Surface of a corona virus consists of several different protein molecules that together form a sphere to encapsulate the RNA molecule that contains all the instructions for making more viruses. There are S, M and E proteins to which antibodies can dock to render the virus harmless. The antibodies predominantly belonged to the IgG class and were directed against the S2 subunit. In particular, donor sera not infected with SARS-CoV-2 showed a specific neutralizing activity against SARS-CoV-2 which was comparable in effect to that of Covid-19 patients.
Up to 62 percent of children have antibodies
Together, the results from four independent tests showed the presence of pre-existing immunity to SARS-CoV-2 in non-infected individuals. In samples from 50 pregnant women not infected with SARS-CoV-2, at least 5 of these samples from May 2018 showed low concentrations of SARS-CoV-2 S-reactive IgG antibodies. Another 2 samples reacted with N, but not with S or S1.
These data suggest that at least 10 percent of these subjects had existing antibodies that can turn off SARS-CoV-2.
In fact, the frequency of infection with each HCoV type shows a characteristic age distribution in children and adolescents. A group of younger healthy children aged 1-16 years not infected with SARS-CoV-2 were also examined. Remarkably, at least 21 of these 48 donors had easily detectable amounts of SARS-CoV-2 S-reactive IgG antibodies.
The presence of SARS-CoV-2 S-reactive IgG antibodies increased with age and peaked at 62 percent after 6 years. The higher values are attributed to frequently repeated infections of children and adolescents with the corona cold viruses. These seem to offer even more protection than infection with SARS-Cov-2, as the antibodies disappear fairly quickly and apparently also completely disappear.
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