Assessment of effective mitigation and prediction of the spread of SARS-CoV-2 in Germany using demographic information and spatial resolution

Abstract

Non-pharmaceutical interventions (NPIs) are important to mitigate the spread of infectious diseases as long as no vaccination or outstanding medical treatments are available. We assess the effectiveness of the sets of non-pharmaceutical interventions that were in place during the course of the Coronavirus disease 2019 (Covid-19) pandemic in Germany. Our results are based on hybrid models, combining SIR-type models on local scales with spatial resolution. In order to account for the age-dependence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we include realistic prepandemic and recently recorded contact patterns between age groups. The implementation of non-pharmaceutical interventions will occur on changed contact patterns, improved isolation, or reduced infectiousness when, e.g., wearing masks. In order to account for spatial heterogeneity, we use a graph approach and we include high-quality information on commuting activities combined with traveling information from social networks. The remaining uncertainty will be accounted for by a large number of randomized simulation runs. Based on the derived factors for the effectiveness of different non-pharmaceutical interventions over the past months, we provide different forecast scenarios for the upcoming time.

Appropriate relaxation of non-pharmaceutical interventions minimizes the risk of a resurgence in SARS-CoV-2 infections in spite of the Delta variant

“…The base model in this paper corresponds to our previously developed SIR-type model in [6]. In order to sufficiently represent reality with our compartmental model, we use two key ingredients: First, we divide the total population into different age groups that each have their own set of epidemiological parameters as well as their own contact patterns.…”

“…SIR-type model for one German county. We omit the age-dependence index i as well as the compartments C + and I + for clarity; the blue boxes represent compartments that have been newly added for the vaccination model; see [6] for a full description of the parameters. Here,…”

“…The range of contact patterns depends on the NPIs. The baseline and minimum number of contacts φ B,i,j and φ M,i,j is obtained from [18,19] as described in [6,Sec. 3.2].…”

“…To account for the Alpha variant in Germany [20, Report of Apr. 7], we use a 1.4 times increased value for the transmission risk ρ i [21] compared to the wild-type considered in [6]. The Delta variant of SARS-CoV-2 has already reached Germany and made up approximately 48% -59% of the different variants by July 4 [22, Situation Report of July, 7].…”

“…We do not intend to provide precise forecasts with our simulations. Instead, we focus on the comparison of different strategies based on our mathematical model that was already validated in [6].…”