key: cord-0692049-fhdbmplr
authors: La Maestra, Sebastiano; Abbondandolo, Angelo; De Flora, Silvio
title: Epidemiological trends of COVID‐19 epidemic in Italy over March 2020: From 1000 to 100 000 cases
date: 2020-05-12
journal: J Med Virol
DOI: 10.1002/jmv.25908
sha: f62ba54617f0c182f803bd73ffb72b3ee26c6c26
doc_id: 692049
cord_uid: fhdbmplr

The coronavirus disease 2019 epidemic started in Italy by the end of January 2020 and, after 1 month, it affected 1049 persons. Based on the Italian Ministry of Health data, we reconstructed the daily course of virus‐positive cases and deaths over March 2020 for the whole of Italy, 19 regions and 2 provinces. From 29 February to 31 March, there was a 100.9‐fold increase in the cumulative number of cases and a 428.6‐fold increase in the number of deaths in Italy. When plotted on a semilogarithmic scale, the curves tended to diverge from linearity with 23%, 16%, and 7% average daily increases during the three decades of March. Similarly, the number of deaths decreased from an average daily growth of 19% over the second decade to 10% over the third decade. The correlation coefficients relating the days to cases or deaths over each one of the three decades approached unity. As inferred from the equations of the regression lines relative to the three decades, the doubling times of cases were 3.4, 5.1, and 9.6 days, respectively. The doubling times of deaths over the second and third decades were 4.9 and 7.0 days, respectively. There was a broad geographic variability, with a striking gradient from the North, where 40.8% of cases and 57.9% of deaths occurred in Lombardy, to the South. On the whole, over March there was a trend to epidemic growth decline but the time for the end of the epidemic will depend on a variety of factors and, at present, it is unpredictable.

The coronavirus disease 2019 (COVID-19) epidemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), officially started on 31 December 2019 in the city of Wuhan, in the Hubei province of China, 1 and thereafter spread to many other countries in the world according to asynchronous patterns, which is typical for infectious diseases due to multiple contagion sources. On 30 January 2020, the outbreak was declared a Public Health Emergency of International Concern; on 11 March, it was characterized as a pandemic by WHO, and in a matter of weeks, it affected over 100 countries. 2 The earliest appearance of COVID-19 in Italy was on 30 January, when a couple of Chinese tourists were found to be positive for SARS-CoV-2 in Rome. 3 Thereafter, an outbreak of SARS-CoV-2 infections started in Lombardy on 21 February and it grew progressively over the national territory with striking regional differences. On 29 February, 1049 persons were positive for the presence of the virus in Italy. 4 Since 28 February, the national and regional authorities have implemented a series of directives concerning extraordinary interventions and hygienic guidelines.

More and more stringent protocols have involved exceptional and unprecedented lockdown measures and the shutdown of most industrial and commercial activities, which is having a massive impact from social and economic standpoints.

The goal of the present study was to reconstruct the course and trends of the COVID-19 epidemic in Italy and in all individual Italian regions over the month of March 2020.

The number of COVID-19 cases, confirmed by positivity for SARS-CoV-2 of nasopharyngeal swabs analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR), and the number of deaths ascribed to COVID-19 were taken from the daily reports of the Italian Ministry for Health. 4 The data were recorded for Italy 

The graph reported in Figure 1 shows the cumulative numbers of 

The graph shows the cumulative numbers of COVID-19 cases (blue symbols), confirmed by positivity of nasopharyngeal swabs for SARS-CoV-2, and of deaths (red symbols) ascribed to COVID-19 in Italy from 1 to 31 March 2020. The data are plotted on a semilogarithmic scale. Two vertical lines were traced in correspondence of 10 and 21 March, thus dividing the month into three periods, from 1 to 10 March, 11 to 21, and 22 to 31. The straight lines are the three regression lines for cases (in blue) and the two regression lines for deaths (in red). See text for details. COVID-19, coronavirus disease 2019; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2 were 4.9 and 7.0 days, respectively. The interval between the two curves ranged between 13 and 21 days, which should not be taken as the time elapsing between the diagnosis of the disease and death because the curve relative to cases also includes a 90% of survivors.

The map of Italy represented in Figure 2 4 Although we could not proceed to a detailed analysis of regional data as we did for the whole national territory, the observation of the graphs reported in With 100 000 cases in 1 month, the morbidity data for COVID-19 are impressive and depict a dramatic scenario also for reasons that we discuss below, the actual numbers are likely to be substantially higher than the official ones. The magnitude of these figures should be evaluated in conjunction with the burden of seasonal influenza-like illnesses (ILI). From the 42nd week of 2019 to the 11th week of 2020, more than 7 million ILI cases were reported in Italy. 6 Note that the estimated ILI cases during the past cold season would indicate that about 12% of Italians had been affected by ILI, which does not appear to be a particularly high proportion compared to other previous seasons. March 2020, more than half a million swab tests were carried out in Italy. 4, 9 Paucisymptomatic illnesses are not tested for the presence of SARS-COVIR-2 and, even more, a so-far unquantifiable proportion of infections are fully asymptomatic. The iceberg phenomenon is a common event in many infectious diseases due to the presence of either healthy carriers, who do not develop any symptoms, or early carriers, who start to be contagious during the incubation period of the disease before the clinical onset. At the end of the epidemic, with the development of reliable and validated methodologies, it will be possible to carry out seroepidemiological studies and to analyze specific antibodies in broad population strata thereby evaluating the spread of the infection as related to gender, age, geographical distribution, working activities, etc. This will also be extremely useful to design preventive strategies for the future. Lombardy an outstanding number of cases was recorded not only in the province of Milan, the regional capital (8911 cases as to 31

March, 3.26 million inhabitants, accounting for 273 cases/100 000), but even more in smaller provinces, such as Bergamo (8803 cases, 1.12 million inhabitants, accounting for 791 cases/100 000) and

Brescia (8367 cases, 1.27 million inhabitants, accounting for 658 cases/100 000). We refer to reports communicated by the Italian Ministry of Health 4 and by the Italian National Institute of Health (Istituto Superiore di Sanità) 12 for a detailed analysis and graphical representation of data in all the individual Italian provinces.

As it is evident from the graphs shown in Figures 3-5 In conclusion, by the end of March 2020 the numbers of COVID-19 cumulative cases and deaths were still growing in Italy. However, the herein reported data provide evidence that there is a time-related trend of a progressive horizontalization of the regression lines. The regression line will hopefully become horizontal in the future thereby testifying to a zero growth in the number of cumulative cases. At present, the time for such an achievement is unpredictable. It will depend on how Northern regions will be able to attenuate the spread of SARS-CoV-2 in the population and on how the other Italian regions will avoid the risk of contagion by respecting the containment measures even at the expense of enormous familiar, social, productive, and economic sacrifices.

Early transmission dynamics in Wuhan, China, of novel coronavirus-infected pneumonia

COVID-19 and Italy: what next?

The first two cases of 2019-nCoV in Italy: where they come from

World Health Rankings. Italy: influenza and pneumonia

Case-fatality rate and characteristics of patients dying in relation to COVID-19 in Italy

Coronavirus disease 2019 (COVID-19) in Italy

Critical Care Utilization for the COVID-19 outbreak in Lombardy, Italy: early experience and forecast during an emergency response

Genomic characterization and phylogenetic analysis of SARS-COV-2 in Italy

Epidemiological trends of COVID-19 epidemic in Italy over March 2020: From 1000 to 100 000 cases

We thank Alberto Abbondandolo (Fakultät für Mathematik, Ruhr-Universität Bochum, Germany) for assistance in the mathematical analysis of data.

http://orcid.org/0000-0002-8023-5541