Wrong corona incidences in Hamburg: How could that happen?

Created: 01/19/2022 15:19

By: Nadja Austel

Peter Tschentscher in the mayor's office in the town hall.

© Marcus Brandt/dpa/archive image

In Hamburg, a comparison was made between new corona infections in unvaccinated and vaccinated people using incorrect figures.

Frankfurt – Peter Tschentscher (SPD)*, Mayor of Hamburg, was sharply criticized in early December 2021*. He had announced in an official press conference that the proportion of unvaccinated people among the new Corona * infected people was over 90 percent. This number was illustrated with a graphic: In calendar week 45 there were 3452 new infections with the corona virus in Hamburg. Of these, 91.5 percent were unvaccinated and 8.5 percent were vaccinated. This discrepancy sounds drastic - and had to be corrected afterwards.

MP Anna von Treuenfels (FDP*) had asked the Hamburg Senate for the specific figures on which the calculation was based.

The answer and the numbers it contains are available to the NDR and the world.

After examining them, it became clear that the vaccination status of the vast majority of those infected was not known at all.

Hamburg: Corona case numbers of unvaccinated people are massively distorted

The actual data was therefore: Only 14.3 percent of those infected were unvaccinated, 22.5 percent were proven to be vaccinated, and the vaccination status of the not inconsiderable “rest” of 63.2 percent was simply unknown.

But even if all people whose vaccination status could not be determined were counted among the unvaccinated, this does not result in the 91.5 percent published by Tschentscher (but 77.5 percent).

This was justified in retrospect with the time delay with which data was partially entered later.

This can happen if, for example, a person has submitted their vaccination certificate later.

In addition, given the escalation in the number of new infections, it was no longer possible for the health authorities to collect all the data promptly and completely.

According to Tschentscher, there were also IT problems.

Cases in which the vaccination status was unclear were therefore also included in the value for unvaccinated persons.

Corona statistics: Logical errors in comparability in Hamburg

But even if all the data is available in time and in full, there is an important difference between the groups of unvaccinated and vaccinated: In the recent past, unvaccinated people had to present current corona tests much more frequently due to 3G regulations.

This is fatal for the statistical comparability of the two groups, because, as is well known, many Covid diseases are completely asymptomatic.

Those infected have neither a runny nose nor a cough.

However, these silent infections are also detected more frequently through frequent testing in unvaccinated people, which in turn influences the numbers.

Corona pandemic: Hamburg's mayor regrets "data breach"

The two groups could be compared mathematically, but for this it would have to be recorded whether the infected people show symptoms. The number of asymptomatic cases could then be excluded. Thus, symptomatic infections in unvaccinated subjects are compared with symptomatic infections in vaccinated subjects.

Tschentscher addressed this "data breach" again at the state press conference (01/11/2022): "At the time, we didn't even have the idea that it had to be restricted so much," he said. "We would like to justify our measures in a plausible and convincing manner - and that includes correct figures," said Tschentscher after the Senate meeting. "I very much regret the uncertainty that has arisen as a result." Critics had accused the SPD politician of intentionally presenting the citizens with false figures in order to justify corona measures.

The mayor firmly rejected allegations of deception: "At the time of publication, nobody was aware that there was this gross deviation from reality." No wrong decisions had been made on the basis of the data, because the trend in the numbers remained the same.

(na/dpa/lno)

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