For this report, we focused on what is happening in the Cologne region; based on the results, we can confirm that our model and/or the resulting findings are not only applicable to Berlin, but can also be applied to other metropolitan regions.

The current situation is consistent with a generally subcritical situation (R-value < 1), associated with a rather high incidence import by travelers returning up until the end of the school vacations, followed by increased incidences in schools that this causes. This, however, could be lowered in the meantime, especially in Cologne. This results an estimate of which measures at schools are sufficiently effective.

For the fall or winter, our model still results in a supercritical situation (R-value > 1) as soon as most of the leisure activities again take place indoors. The dynamics of this development in the model depend on rather small changes; overloading of hospitals is possible according to the model, but not assured. Accordingly, we recommend monitoring the reporting and hospital incidences.

If developments lead to an overloading of hospitals, according to our model very significant measures would be necessary to then push the R-value back below 1. According to our model, this could be achieved by ramping up the rapid testing strategy again, where (1) indoor recreational activities would have to be particularly targeted, and (2) it would be essential to include the vaccinated/genetically active in the testing strategy, as they rarely develop severe courses but are nonetheless involved in transmission.
