Correlating USA COVID-19 cases at epidemic onset days to domestic flights passenger inflows by state

Abstract

In the USA, COVID-19 first infection cases were imported by external travelers. At the epidemic onset days, we assume that the disease partially spreads due to domestic passengers air transportation in its densely connected airport network. Taking into account all USA states, we arranged COVID-19 infected cases data in a convenient common time origin timeline as if the beginning of the epidemic would have occurred simultaneously in every state. Looking for a trend between cases and air passengers, we obtained with this timeline very good statistical Pearson and Spearman correlations between accumulated infected cases by state and a positive power of the product [Formula: see text], where [Formula: see text] is the domestic flight passengers (travelers) inflow by state before the epidemic and [Formula: see text] is its population. We also found a good correlation between percentages of urban area by state and their COVID-19 daily new cases growth rates at onset days.