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1. Covid-19: Recovering Estimates of the Infected Fatality Rate During an Ongoing Pandemic Through Partial Data

Author:
Matteo Villa, James F. Myers, and Federico Turkheimer
Publication Date:
05-2020
Content Type:
Commentary and Analysis
Institution:
Italian Institute for International Political Studies (ISPI)
Abstract:
In an ongoing epidemic, the case fatality rate is not a reliable estimate of a disease’s severity. This is particularly so when a large share of asymptomatic or pauci-symptomatic patients escape testing, or when overwhelmed healthcare systems are forced to limit testing further to severe cases only. By leveraging data on COVID-19, we propose a novel way to estimate a disease’s infected fatality rate, the true lethality of the disease, in the presence of sparse and partial information. We show that this is feasible when the disease has turned into a pandemic and data comes from a large number of countries, or regions within countries, as long as testing strategies vary sufficiently. For Italy, our method estimates an IFR of 1.1% (95% CI: 0.2% – 2.1%), which is strongly in line with other methods. At the global level, our method estimates an IFR of 1.6% (95% CI: 1.1% – 2.1%). This method also allows us to show that the IFR varies according to each country’s age structure and healthcare capacity.
Topic:
Health, Pandemic, Data, and COVID-19
Political Geography:
Europe, Italy, and Global Focus

2. Covid-19 and Italy’s Case Fatality Rate: What’s the Catch?

Author:
Matteo Villa
Publication Date:
03-2020
Content Type:
Commentary and Analysis
Institution:
Italian Institute for International Political Studies (ISPI)
Abstract:
COVID-19’s lethality in Italy is a highly discussed figure. When compared with other major countries, Italy’s 9.9% case fatality rate (CFR) as of 24 March 2020 is the highest by far. But relying on this figure is misleading. By itself, the CFR tells us almost nothing about COVID-19’s plausible lethality (infected fatality rate, or IFR). On the opposite, recent studies place China’s IFR at 0.7%. By relying on this figure, ISPI’s best estimate for COVID-19’s plausible lethality in Italy is 1.1%. The gap between the IFR and the CFR figures can be largely attributed to the number of infected persons that have not been tested and, therefore, escape counting. ISPI estimates that the number of active cases in Italy is at around 530,000 as of 24 March 2020, or almost ten times larger than the official count of 55,000 active cases. This paper shows that the CFR is an unreliable indicator of COVID-19’s plausible lethality, and there is not enough evidence to suggest that Italy’s IFR is much higher than expected. On the opposite, a direct comparison between the CFR and the IFR is much better placed to paint a more realistic picture of the evolution of the ongoing epidemic.
Topic:
Health, Pandemic, Data, and COVID-19
Political Geography:
Europe and Italy