The Role of Population Density and Contact Rates for 2009 A (H1N1) and Covid-19 Pandemics

Abstract

Essential properties of the standart Susceptible-Infected-Removed (SIR) model are characterized in terms of the parameter, R_0, known as the basic reproduction number.In the present work, we investigate the dependency of R_0 on contact rates in two distinct cases, the 2009 A(H1N1) pandemic for the Netherlands and Istanbul, and the Covid-19 pandemic for the federal states of Germany. For the data from the 2009 A(H1N1) pandemic, encompassing seven European countries (including the Netherlands) and Istanbul, Turkey, we show that the basic reproduction number is proportional to the population density. We observe in particular that for the Netherlands and for Istanbul, high population densities may give rise to parameters that lie well outside the accepted ranges in the literature. In addition, for the data from the period between February and June 2020, during the Covid-19 pandemic in the federal states of Germany, we observe that inhomogeneities in a population dominate the effects of population density, possibly due to the curfew and travel restriction practices in force during that period enhence the role of household dynamics. We also observe for the federal states of Germany for the Covid-19 pandemic that demographic factors exert a significant influence on the contact rate and consequently impact the determination of R_0.