Describing the COVID-19 outbreak during the lockdown: fitting modified SIR models to data
- PDF / 953,573 Bytes
- 10 Pages / 439.37 x 666.142 pts Page_size
- 11 Downloads / 149 Views
Describing the COVID-19 outbreak during the lockdown: fitting modified SIR models to data Aldo Ianni, Nicola Rossia Laboratori Nazionali del Gran Sasso – INFN, Via Acitelli 22, 67100 Assergi, Italy Received: 3 September 2020 / Accepted: 28 October 2020 © Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract In this paper, we analyse the COVID-19 outbreak data with simple modifications of the SIR compartmental model, in order to understand the time evolution of the cases in Italy and Germany, during the first half of 2020. Even if the complexity of the pandemic cannot be easily described, we show that our models are suitable for understanding the data during the application of the social distancing and the lockdown. We compare and contrast different modifications of the SIR model showing the strengths and the weaknesses of each approach. Finally, we discuss the reliability of the model predictions for estimating the nearand far-future evolution of the outbreak.
1 Introduction The Coronavirus Disease, named COVID-19, is an infectious disease caused by the newly discovered coronavirus SARS-CoV-2 [1]. Most people infected with the COVID-19 virus experiences from mild to moderate respiratory illness and recover without requiring special treatment. Older people and those with underlying pre-existing medical problems like cardiovascular diseases, diabetes, chronic respiratory diseases, and cancer are more likely to develop serious illness. Yet, at present much needs to be understood about the effects of this new virus. COVID-19 spreads quickly, mainly through droplets of saliva or discharge from the nose when an infected person coughs or sneezes. The coronavirus inside airborne droplets can survive for many tens of minutes and eventually sticks to surfaces and remains active up to many hours, depending on materials [2]. This fact could further increase the diffusion of the outbreak. The velocity of the outbreak spread is described by the so-called basic reproduction number (or ratio), usually referred to as R0 , defined as the expected number of new infections from a single new case in a population where all subjects are susceptible. The lockdown and/or the social distancing should help in reducing R0 , making the outbreak duration shorter than the typical time needed by the free natural evolution until the so-called herd immunity is reached. Another important feature of COVID-19, and in general for outbreaks in progress, is the impossibility of quantifying the asymptomatic population. Many ongoing studies, as, for example, [3], are indeed showing that this component could be a substantial fraction of
a e-mail: [email protected] (corresponding author)
0123456789().: V,-vol
123
885
Page 2 of 10
Eur. Phys. J. Plus
(2020) 135:885
the visible cases, i.e. the ones detected by reliable medical tests. Even if not detected, the asymptomatic cases can play an important role in the diffusion of the coronavirus epidemic and can drastically change the outcome of the mode
Data Loading...
