According to the results of the so-called heinsberg study, 1.8 million people in germany could have been infected with the coronavirus by now. This is the result of an estimate based on a model calculation, the university of bonn announced on monday.
A leading epidemiologist made a cautious comment. The researchers led by virologist hendrik streeck based their estimate on the number of people infected in the community of gangelt in the district of heinsberg and the mortality rate calculated there for corona infection. The researchers assume that 0.37 percent of those infected in gangelt died. However, only seven deaths were included in the calculation of the mortality rate.
From these data they calculated a theoretical number for germany. In principle, this works like this: the researchers assume that mortality is roughly the same throughout germany. So if it is known how many infected people there are for every dead person, then the number of deceased people, which the RKI puts at more than 6,500, can be used to estimate the number of people who are actually infected – including those who have not been recorded.
"Of course, you always have to take that with a grain of salt, it’s an estimate," streeck told the german press agency. Gerard krause, head of the epidemiology department at the helmholtz center for infection research (HZI) in braunschweig, warned in a video conference with journalists against applying the figures from gangelt to the whole of germany. "I’m rather reluctant", he said.
It could be argued, for example, that the proportion of corona deaths in gangelt is unusually low. It is conceivable that the spread of the virus in senior citizens’ homes – as has been observed in recent weeks – is not yet reflected in the study. In the model calculation, due to the small size of the community, a single death also has a greater or lesser impact. Overall, however, krause called the data of the study "very convincing".
A team of researchers led by streeck had surveyed 919 residents in 405 households in gangelt on the dutch border and conducted corona tests. Many burghers in the town were infected with the new virus after a carnival session in mid-february. The community is therefore considered the epicenter of the virus. The situation is only comparable to a limited extent with other regions of germany – for example, the number of infected people is higher in gangelt. The researchers also point this out in their study. Seven deaths were included in the calculation of the mortality rate. In the sample, children were slightly underrepresented and older people slightly overrepresented.
The setting of the study – in addition to the public relations work by the berlin agency storymachine – had attracted criticism. The study had been commissioned by the NRW state government. The state government did not want to comment on the study on monday.
According to the university of bonn, the study focused on the infection fatality rate (IFR), which indicates the proportion of deaths among those infected. According to the study, 15 percent of people in gangelt were infected – the infection mortality rate was 0.37 percent. This mortality rate could be used "as an estimate to extrapolate that to germany," streeck told dpa.
"In order to make model calculations about how the virus will affect the population, we need key data to improve the models," said streeck. Until now, a range of 0.2 to 1.5 percent mortality rate was assumed, the world health organization (WHO) even spoke of 3.4 percent. "With this study, we can now reduce this range to a much smaller error range."
According to the results, 22 percent of those infected in gangelt showed "no symptoms at all". Some of them didn’t even know they were sick until the test was taken. Martin exner, head of the institute for hygiene and public health and co-author of the study, said, according to the release: "every supposedly healthy person we meet can unknowingly carry the virus. We have to be aware of that and act like it."This confirms the importance of general distance and hygiene rules in the corona pandemic.
Another point that could be interesting for the practice is the strong connection with the carnival session, said streeck. It was noticeable that people who had taken part in the carnival session had corona symptoms more frequently. The question is therefore whether physical proximity to other revelers and increased droplet formation due to loud talking and singing contributed to a more severe course of the disease. Further studies are planned, explained gunther hartmann, co-author of the study and director of the institute for clinical chemistry and clinical pharmacology at the university of bonn.