Introduction

Italy was the first western country to be strongly hit by the COVID-19 outbreak. The first relevant clusters of infection were officially registered in two northern Italian regions (Codogno in Lombardy, and Vo’ in Veneto) on 21 February 2020. At that time, scientific information about COVID-19 and its potential dangers was still very scarce. The WHO did not proclaim COVID-19 as a ‘high global risk’ until 28 February 2020: on that same day, Italy already had 888 officially infected persons, 345 hospitalised COVID-19 patients, 105 patients in intensive therapy units (ICUs), and 21 deaths (open data from Protezione Civile).

Considering the total number of COVID-19 infections during the first phase of the pandemic, the cases counted at the end of May 2020 were 232,639. However, the peak was reached in March 2020, with 113,351, while in the following months, the trend decreased, reaching ‘only’ 22,893 cases in May 2020 (ISTAT -ISS, 2020).

According to available data, more than 70 per cent of positive cases reported between February and May 2020 were concentrated in a limited number of Northern Italian provinces in which the circulation of the infection was exceptionally high (that is, COVID-19 infection higher than 450 cases per 1000 residents) (ISTAT -ISS, 2020).