Explaining Wuhan’s epidemic and subsequent northern hemisphere epidemics

Abstract

We aimed to use computer simulation modeling of large datasets to explain the experience of Wuhan, China, and compare other global experiences based upon the assumptions that correctly predicted the course of the epidemic in Wuhan. We used a propagmath simulation tool to simulate different Wuhan epidemic trajectories to see how they could fit with what is reported or explained in the literature. We proceeded to multiple simulations to explore which ones would fit end points. These simulations are available at

http://157.245.67.202/propagmath/RegionView/103. All scenarios meeting the specified outcomes were consistent with sufficient collective protection having been reached before the stay home mandate was lifted or even earlier. This remains true even after adjusting for a slowdown of the reproduction rate in spring and summer. Scenarios in which the virus had some of its natural course before being slowed down lead to a rebound at the times where seasonality is most favorable to the epidemic with a comparable rebound. Some researchers have hypothesized that lockdown and stay home mandate in Wuhan led to virus extermination in the city allowing a return to normal life. No other country or territory in the Northern hemisphere where the virus had reached a significant circulation level succeeded in achieving a similar result. Some countries like Morocco or Israel had very long and strict stay home mandates and failed to exterminate the epidemic sometimes with higher mortality, multiple phases, and longer epidemics than neighboring countries. We offer potential explanations for these differences.