How infectious are children – Controversial Corona study korrigiertDas Team to the German virologist Christian Drosten clarified his controversial statements on the viral load of children: It was not proved that children have a smaller risk of Infection out. Marlene Weiss, Julian Rodemann, Berit Uhlmann46 Kommentare46Kinder can have a large amount of pathogens, whether this be disseminated, therefore, it is not used.Photo: Alessandro della Valle (Keystone)
scientists at the Berlin virologist Christian Drosten have submitted a revised Version of their widely discussed study on the infectivity of children. The work, whose first Version was published at the end of April, to investigate whether children can transfer Sars-CoV-2 as frequently as adults, and compares the virus quantities in the nose and throat of Infected in different age groups.
criticism it was given in particular to the statistical analysis of the data. The new Version is differentiated and partly restrained – the final answers but also provide you hardly. While the core message of the original work is that the virus can distinguish loads of children and adults, significantly, is the choice of words in the new Version is more cautious: “The present study provides little evidence for assumptions that children might not be as infectious as adults.” That children have a smaller risk of Infection out, not to be proved thus.
If the risk of Infection in the two groups are really the same size, but it is difficult to assess made. The criticism of various statisticians adopted by the Team to Drosten. You had criticized how the Team had divided the examined persons in the age groups. To compare, instead of simply children with adults, had divided the researchers, the people in ten age groups – to compare all pairs.
Christian Drosten, Director of the Institute for Virology at the Charité hospital in Berlin. Photo: Christophe Gateau (Keystone)
apart from the fact that many of these comparisons for the original question are of little relevance, the approach to problems: The groups are very small, so that it is difficult to distinguish real differences from chance. In the new Version is now being compared only children with adults. In addition, the researchers distinguish between the two virus used tests. For one of the two, the researchers actually recognize a most likely non-random, but little difference between children and adults. But this could also be due to a different application of the Tests, the scientists write.
Now, the scientists come to the conclusion that the viral load increases in one of the Tests slightly with age, and the other, however, practically remains constant.
In addition, statisticians had criticized that Drosten and his colleagues have not considered the age of individuals as a continuous variable, which it is. Because there should be a connection between age and viral load, so the will not hold securely to the artificial age limits.
Also, this suggestion took the Team. Now, the scientists come to the conclusion that the viral load increases in one of the Tests slightly with age, and the other, however, practically remains constant. The increase in the first Test, the researchers explain that this is more often used in children that are already in the hospital and typically longer than a week ill and, therefore, less virus in the throat have. Thus, with age, increasing virus concentration would be only a dummy effect.
Some statisticians hold the new analysis meaningful. “Convincing reanalysis, which removes my concerns about the statistical methodology completely”, wrote Jörg Stoye, Cornell University on Twitter. In an analysis of the first Version of Drostens work he had come to other conclusions than this. Like many colleagues, he had criticized that the data is pointing at the correct analysis to lower virus loads in children. Dominik Liebl, University of Bonn, says in the methodological part of the statistical analysis had been improved using the criticism from the science now clearly, the “#team science,” as it’s called on Twitter, was functioning so.
“This report can have an undue influence on public opinion and health policy, regardless of whether it is scientifically valid or not.”
David Curtis, University College London
Others see the work more critically. David Curtis of University College London considers that it is in “unacceptably unprofessional”, that was published on a Charité-side instead of on one of the usual Preprint Server, on which other scientists can post comments. “This report can have an undue influence on public opinion and health policy, regardless of whether it is scientifically valid or not,” says Curtis. Something like this should not be discussed among the scientists directly with the Public: “This document should have never be published.”
in Addition, the data had low reliability, in the Original. With the new analysis, other data artifacts become clear. “My view is that they tell us nothing meaningful about the infectivity of children; this should be determined in epidemiological studies,” says Curtis. The Best course would be to ignore the study simply.
recommendation less restrained
In any case, it remains in the knowledge, that even children can have a large amount of pathogens. Still not sure whether people with a high concentration of Virus spread of the pathogen inevitably stronger. The Team Drosten is based on the findings of influenza epidemics, that the viral load is a relevant factor.
The policy implications derived by the scientists from their work, sound still more cautious than before. Originally, the researchers had warned that a full re-opening of schools and kindergartens. Now it means, instead, that a complete re-recording of the lesson, care should be preventive Tests observed.
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