## 1 Introduction  
Data analysis [1; 2; 3] has proved to be of fundamental importance for studying and predicting the behavior of the pandemic of SARS-CoV2 and COVID-19, in order to intervene promptly and stem its spread [4; 5; 6]. The school opening has been a hotly debated topic nationwide and worldwide [7; 8; 9], with at one side scientists that consider schools safe and on the other side scientists who consider schools unsafe and unsecured. In our opinion, school is not a safe environment by definition, but it must be made safe taking serious actions with rigorous protocols and structural interventions as described in [10; 11]. Effects of schools opening and the propagation of COVID-19 are described in other countries, such as in [12] where the effects of school openings on hospitalization in USA are modeled, or in [11] where the authors explain how UK schools are causing COVID-19 spreading and how to act to reduce their impact. The data (shown in Table 1) on the growth of infections by age groups from the beginning of September to March that are published weekly in the epidemiological reports of the ISS (Istituto Superiore Sanita) [www.iss.it] (accessed on 27 April 2021), indicate that the age group 0-9 have had a growth between 6 and 10 times higher than all other ages. (Please note that following the ISS indication, under \(<\)19 young population are mostly asymptomatic with a percentage of 75%. Hence, the ratio of these cases in the younger population is probably much higher than in the elder population. )The data show that from 29 December 2020 to 10 March 2021, the infections increased by 83.44% in the age group between 0 and 9 years. Additionally, 63.55% in the 10-19 age range. The school age is therefore the one where the contagion has grown a little more. The third group for growth is the one between 30 and 39 years, with 52.35% and almost all the other age groups are below 50% growth. The older age groups registered the lowest percentage growth: between the ages of 80 and 89, the contagion grew by 39.71% over the period, and over 90 years even less 31.28%. These data disprove the idea that the problem was that of transport, which essentially concerned the high schools (the youngest ones mostly go to school on foot or are accompanied by their parents by private means). Looking at the data and statements of neighboring countries and with demographic characteristics similar to ours, the situation is already well defined on how much schools are drivers of contagion:  
* In France schools and universities have been indicated as the first factor in active outbreaks [source: Sante Publique France];
* In the UK, primary and secondary school, after careful tracing, was in third place as number of reports [source: NHS Test and Trace UK];
* In Germany, the school was recently declared to be at high risk in some statements made by [PERSON] herself in early February 2021;
* Several papers (recently appeared in the Lancet, Nature and Science), albeit with all the stated limits in the works, show that the closure of schools is the second most impacting factor, as NPI (Non-Pharmaceutical Interventions), on the reduction of the contagiousness index Rt [13,14];
* Further preliminary analyses have been carried out on the Piedmonts Region and national territory by researcher [PERSON] and a clear relation on the increase of cases and the school opening is reported [15];
* The Lazio Region was driven to an emergency state due to school contagion impact [16];
* During the 19 March 2021 Press Conference, the Belgium Prime Minister said: \"From contact analyses, we can also see that schools are key places where many infections happen,\" [PERSON] said.