Epidemic modeling for the resurgence of COVID-19 in Chinese local communities

Abstract

COVID-19 is a constantly challenging global health issue due to its strong intensity, rapid mutation and high infectiousness. The new Delta and Omicron variants have triggered massive outbreaks worldwide. Even China, which has done a good job in outbreak prevention, is still heavily affected by the virus. The long-term fight against multiple COVID-19 outbreaks is ongoing. In this study, we propose an SEIQR model that considers the incubation period and quarantine measurement. We verified our model using actual outbreak data from four Chinese cities. Numerical simulations show that a five-day delay results in a double resurgence scale. Our model can be used as a tool to understand the spread of the virus quantitatively and provide a reference for policymaking accordingly.

Keywords: COVID-19; Mutation; Quarantine; Resurgence; SEIQR model.

Fig. 1

The diagram of the SEIQR model.

Fig. 2

Modeling for resurgence in Nanjing. Parameters are chosen as follows: N = 250; n = 10; n₂=15; n₃=5; β₁=0.3; β₂=0.2; β₃=0.01; β₄=0.001; α=1/N; γ=0.01; γ₁=0.02; γ₂=0.03; γ₃=0.04; γ₄=0.14; γ₅=0.01; δ₁=0.3; δ₂=0.3; σ=1/5; M = 6; m = 2.

Fig. 3

Modeling for resurgence in Yangzhou. Parameters are chosen as follows: N = 600; n = 8; n₂=18; n₃=3; β₁=0.5; β₂=0.3; β₃=0.01; β₄=0.001; α=1/N; γ=0.03; γ₁=0.04; γ₂=0.05; γ₃=0.07; γ₄=0.15; γ₅=0.01; δ₁=0.5; δ₂=0.1; σ=1/7; M = 4; m = 2.

Fig. 4

Modeling for resurgence in Zhengzhou. Parameters are chosen as follows: N = 200; n = 8; n₂=15; n₃₌4; β₁=0.5; β₂=0.3; β₃=0.01; β₄=0.001; α=1/N; γ=0.06; γ₁=0.05; γ₂=0.05; γ₃=0.07; γ₄=0.1; γ₅=0.01; δ₁=0.8; δ₂=0.7; σ=1/5; M = 4; m = 2.

Fig. 5

Effect of the asymptomatic transmission probability with baseline value β₂=0.3.

Fig. 6

Effect of the probability of latent state converted into the infected state, the baseline value is σ=1/5.

Fig. 7

Effect of the probability of transmission from infected into isolated, the baseline value is δ₁=0.8.

Fig. 8

Effect of probability of transmission from asymptomatic into isolated, the baseline value is δ₂=0.5.

Fig. 9

Effect of the number of contact per day, the baseline values are M = 1; n = 5; δ₁=0.8; δ₂=0.5.

Fig. 10

Effect of breakthrough the defense line, the baseline parameter, the baseline values are β₄=0.001; β₃=0.01; m = 2.