Germany will be in lockdown until at least March 7th, only then can nationwide easing of the corona measures be hoped for – if the infection situation in the Federal Republic allows it.
The decision about which facilities are to be opened or closed depends largely on how great the risk of infection is in them. The problem: So far, it has not been possible to say exactly where most people are infected in Germany. The numbers are ambiguous.
But now researchers from the Technical University of Berlin, in cooperation with the Charité Berlin and the Robert Koch Institute, have carried out studies to determine the risk of infection in closed rooms. Your study comes to the result: Offices and schools in particular are dangerous places in the Corona crisis.
Corona infection risk is particularly high in schools and offices
For the study, the researchers developed an infection risk model for various closed rooms. This is based on the length of time a certain number of people spend in the room, the type of activities in it – whether they talk a lot or not, do sports or sit still – and the air currents inside the room. The scientists also assumed that distance and hygiene rules would be observed and that the room would be ventilated regularly.
The researchers then calculated the distribution of aerosols that carry the coronavirus in space. In this way, they also determined the risk of possible contamination in the various scenarios in various closed rooms. This is indicated in the study with a situation-dependent R-value. If the R value is 1, an infected person infects another person in the closed room.
According to the calculations, the highest risk of infection with the highest R value is in fully occupied high schools in which everyday masks are not worn. According to the results of the study, one infected person infects 11.5 others. In a high school that is only half full and does not wear masks, the R value is still 5.8.
There is also a high risk of infection in multi-room offices with a working day of eight hours. If no mask is worn during this, the R value is 8. Even if the office is only half full, it drops to 1.6 with an occupancy of only 20 percent and a mask requirement. According to the study, infections are also likely in restaurants: Even in a half-full restaurant, the R value for a stay of more than one and a half hours is 2.3 – an infected person would therefore infect more than two people with the coronavirus on average.
Low risk in supermarkets, at the hairdresser’s and in local public transport
According to the researchers’ calculations, the risk is lower in supermarkets, at the hairdresser’s or in local public transport.
For a one-hour stay in the supermarket, where all shoppers and employees wear a mask, the R value is only 1. According to the researchers, it is only 0.6 for a two-hour visit to the hairdresser with a mask. And even with a half-hour drive in local public transport with a mask on, it is only 0.8.