The COVID-19 Infection in Italy: A Statistical Study of an Abnormally Severe Disease.

Giuseppe De Natale,Giovanni Di Meglio,Valerio Ricciardi,Vito Marchitelli,Gabriele De Luca,Claudia Troise,Emanuele Spina,Antonio Ferragamo,Dario De Natale,Antonio Scala,Andrea Piccolo,Renato Somma

doi:10.3390/jcm9051564

Abstract

We statistically investigate the Coronavirus Disease 19 (COVID-19) pandemic, which became particularly invasive in Italy in March 2020. We show that the high apparent lethality or case fatality ratio (CFR) observed in Italy, as compared with other countries, is likely biased by a strong underestimation of the number of infection cases. To give a more realistic estimate of the lethality of COVID-19, we use the actual (March 2020) estimates of the infection fatality ratio (IFR) of the pandemic based on the minimum observed CFR and analyze data obtained from the Diamond Princess cruise ship, a good representation of a “laboratory” case-study from an isolated system in which all the people have been tested. From such analyses, we derive more realistic estimates of the real extent of the infection as well as more accurate indicators of how fast the infection propagates. We then isolate the dominant factors causing the abnormal severity of the disease in Italy. Finally, we use the death count—the only data estimated to be reliable enough—to predict the total number of people infected and the interval of time when the infection in Italy could end.

Highlights

The novel viral infection of COVID-19, recently declared a pandemic by the WHO, represents one of the most serious global emergencies of the twenty-first century
While the reported data refer to different stages of the spread of the epidemic, it is important to note that countries at a later epidemic stage than Italy are characterized by a case fatality ratio (CFR) of less than 5%, indicating that the high value of the CFR observed in Italy is not a general characteristic of the epidemic
In addition to the CFR, it is important to obtain a reasonable estimation of the infection fatality ratio (IFR) during the epidemic spread to understand the real hazard of the disease and/or to determine the true number of infected people

Summary

Introduction

The novel viral infection of COVID-19, recently declared a pandemic by the WHO, represents one of the most serious global emergencies of the twenty-first century. The epidemic was first detected in the city of Wuhan, China at the end of December 2019. After a period of inaction and data suppression, the government of China showed serious concern and implemented very severe measures in the Hubei province, the centre of the epidemic, to contain the spread of the infection. 45 days after the first detection (mid-February 2020), the epidemics started to seriously affect several other countries (South Korea among the first, as it borders China). Since the end of February, infections flared up in Italy and Iran for less clear reasons and, since mid-March 2020, the epidemic has spread throughout Europe, in the USA, and many other countries [1]

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