Berlin (dpa) - In a revised version of his study on the infectivity of children in the corona crisis, the research team around the Berlin virologist Christian Drosten sticks to his fundamental statement.

There is no evidence that children with regard to Sars-CoV-2 are not as contagious as adults, the updated version of the study said. It has not yet appeared in a peer-reviewed journal, but has been published as a preprint.

A first draft of the investigation had been published at the end of April and had led to criticism and sometimes violent arguments. The statement back then was that children carry the same high viral load as adults - and are therefore probably just as contagious. Based on these results, the researchers had warned of unrestricted opening of schools and kindergartens in Germany. The new version states: "The unrestricted opening of these facilities should be carefully monitored with the help of preventive diagnostic tests."

Above all, there had been criticism of the statistical evaluation of the data. The methods used are not suitable, scientists said, among other things. However, the critics later emphasized that such discussions were normal in science and criticism of the method did not necessarily call into question the result. Drosten admitted that the statistical methods were rather crude, but stuck to the testimony of the study.

"In my opinion, the comments that existed on the statistical analysis of the first version are convincingly incorporated into the new version of the study," says Christoph Rothe, a statistician from the University of Mannheim at the request of the German Press Agency after a first review of the revised version Results. He was one of the researchers who criticized the statistical methods in the original analysis.

The statistician Dominik Liebl from the University of Bonn, who also dealt with the first version of the Drosten study, wrote on dpa request: In his view, the methodological part of the statistical analysis in the new version had been significantly improved. Liebl adds: "The new version of the preprint will certainly continue to be discussed in science, and that's a good thing."

In the revision presented, the team analyzed the data from a total of 3303 Sars CoV-2 infected people. They found that 29 percent of primary school children (0 to 6 years old), 37 percent of children between 0 and 19 years old and 51 percent of those over 20 years of age found a virus that is probably sufficient for infection. The differences between the groups could also be due to the different application of the tests. "We conclude that a significant proportion of infected people of all ages - including those with no or mild symptoms - carry a viral load that is likely to mean infectivity."

Study revised version

Study first version