The data situation over Christmas is poor; due to a presumably high number of follow-up registrations and retesting, the figures from Christmas to the first week of January are likely to be hardly interpretable. We are therefore guided by the hospital figures in Berlin. These have been showing a downward trend since the beginning of the new year, consistent with a variant of our model.

This model variant predicts further declining infection figures if the population continues to behave at least as restricted as at the beginning of January. However, experience from the spring suggests that the population is more likely to return to normal mobility patterns. This must be avoided at all costs, possibly with further restrictions again in formal terms.

The **new virus variant B.1.1.7** was integrated into our latest models. The results show that the new variant will spread area-wide within 2-3 months and become the dominant variant if a 70% increased infectiousness is assumed. This is relatively independent of the specific regime. The scope for relaxation of measures thus becomes even smaller.

From our simulations, we show the contributions of the different activity types to the reinfection rate "R". As is well known, the sum of these contributions must remain below 1 to significantly reduce the number of new infections. However, each infectious person on average already infects 0.4 other people at home; this would increase to about 0.5 with the new virus variant. This means that the margin is reduced for two reasons: firstly, the expected domestic infections leave less room for maneuvering, and secondly, reinfections during activities outside the home also increase as a result of the new virus variant. Strict maintenance of the reduction of out-of-home activities, as we observed in early January, or even a possible tightening thereof, is sufficient and necessary according to our simulations. In addition, for workplaces "FFP2" masks should also be targeted in work areas outside of single rooms and home office.

Furthermore, we consider an **evening and night curfew** to be a measure that can be implemented quickly and which is effective, e.g., to react to a too-slow decline in the number of infections. In our opinion, school openings should only be considered with FFP2 masks, even during lessons, and only with alternating lessons.
