Global dynamics of a space-age structured covid-19 model coupling within-host infection and between-host transmission

Abstract

To investigate the joint impact of infection age, spatial diffusion and SARS-CoV-2 infection processes on the threshold dynamic of covid-19 transmission among population, we formulate a space-age structured covid-19 model at individual and population levels. The next generation operator ℛ and the basic reproduction number R0 are presented. The disease-free equilibrium is globally asymptotically stable when R0<1, and the age-dependent endemic steady state is globally asymptotically stable when R0>1. Finally, we perform numerical simulations based on the confirmed cases from February 21 to March 30, 2022 in Hong Kong, which suggest that (1) the spacial diffusion and infection age play the crucial role in the transmission of covid-19, so they cannot be ignored; (2) it is particularly important to quarantine and treat infected individuals with symptoms, so as to make better use of medical resources and effectively control the deterioration of covid-19. The control of asymptomatic infections cannot be relaxed which can effectively reduce the potential risk of the disease outbreaks; (3) timely and effective treatment can significantly reduce the proportion of severely infected individuals in confirmed cases, which is also one of primary goals to be achieved by taking control measures.