Modeling the COVID-19 outbreaks and the effectiveness of the containment measures adopted across countries

Edward De Brouwer; Daniele Raimondi; Yves Moreau

en those two age groups, but also by lower testing among younger individuals because they might have been considered at very low risk of complications and/or unlikely to be infectious. The information available does not allow us to discriminate between those explanations. Moreover, the assumption that the case fatality rate in South Korea and (north) Italy is identical is subject to discussion as physicians in South Korea are more experienced in managing patients suffering from Acute Respiratory Distress Syndrome following the 2015 Middle East Respiratory Syndrome (MERS) epidemic in South Korea. Moreover, every country adopted its own specific strategy for testing and reporting of cases, resulting in heterogeneity of the COVID-19 data coming from different countries. For example, South Korea opted for blanket testing of its population and selective quarantine of the positive cases, while Italy focused on testing high-risk and symptomatic subjects and generalized lockdown of the country to reduce the R 0 by acting on the frequency of social contacts. Even within the same country, the reporting strategy changed over time in some cases, leaving a trace in the data. For example, the number of daily new cases in China presents an unlikely spike of 14,108 new cases in a single day (February 12, 2020) because of a change in the reporting strategy, since also clinically diagnosed COVID-19 cases started to be included in the cases count, alongside laboratory tests. This measure was probably necessary to overcome the saturation of the maximum number of tests that could be performed every day, but caused the sudden inclusion of previous "suspect" cases in the official count. Similarly, Italy opted for testing only high-risk individuals and symptomatic cases from February 26, 2020 on (15) .