Sequential data assimilation of the stochastic SEIR epidemic model for regional COVID-19 dynamics

Ralf Engbert; Maximilian M. Rabe; Reinhold Kliegl; Sebastian Reich

for the majority of cases. Analyses of the differences between Referenz-and Meldedatum suggest a very broad distribution with a mode and median of about five days. Thus, the current simulations incorporate an underestimation of the disease time. Linking back to the potential of NPI to control COVID19 until vaccination or medicine is available we close with an observation relating to a recent study [8] . Our analyses covered the same time span as Dehning et al. [8] and we also picked up a systematic pattern of contact reduction which we interpret as a weekly cycle (see Statistical modeling of trends and weekly oscillations). Indeed, the dates of the interventions analyzed by Dehning et al. are confounded with day of the week; the three dates refer to three Sundays in March. It is reasonable to assume that in Germany there is much less contact to persons outside the family context on weekends than during working days. Of course, there are also other reasons why certified reports of COVID19 infections are less frequent for weekends. For example, people are more likely to go to their GP on Monday than to the emergency room on Sunday, especially as long as the symptoms are mild. No reason, in our opinion, is a lack of recording at the RKI; the cases reported for the weekend are added on Monday and Tuesday. One advantage of the method proposed here is that we recover effects with comparatively little data at the level of regions, not an entire country. In the absence of a vaccine or of medication, having such an 7 . CC-BY 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.