7/5/2024
The results of the CCM 2020 project Innovative early-warning approaches in schools during the pandemic period were presented as part of the XLVIII IEA congress during the session dedicated to health promotion and prevention. The project, of which the Regional Health Agency was the leader, involved 4 regions: Tuscany, Veneto, Puglia and Friuli Venezia-Giulia.
L’objective of the study was to develop and testin a time of pandemic emergency, screening procedures in schools for the identification of asymptomatic cases of COVID-19 in the school population aged between 14 and 19 years.
In fact, during the pandemic period the closure of schools was one of the first measures implemented to reduce the transmission of COVID-19. Despite the lower aggressiveness of the virus found in the school population, the evidence showed how students represented a potential vehicle of the virus, determining a risk for the circulation of the SARS-CoV-2 virus and for the possible contagion of fragile subjects in contexts such as example the family unit. The high mobility of students, as well as the promiscuity of school environments, have sparked public debate in trying to define the most appropriate containment measures to adopt to reduce the risk of spreading the virus. Hence the need to define how to intercept asymptomatic cases within the school population, to try to reduce the risk of contagion and reduce the circulation of the virus.
Therefore, the CCM 2020 project was born from the need to study the pandemic in its acute phase on the one hand and, on the other, from the desire to experiment with methodologies to contain the spread of the SARS-CoV-2 virus within institutions schools in the participating regions.
With the aim of evaluating the effectiveness of screening procedures in the school context, compared to the standard procedures envisaged for the containment of the spread of the virus at a regional level, it was deemed necessary to carry out a comparison between schools treated, or subjected to screening, with of control schools.
For this purpose, a rotational screening plan was implemented on students (14-19 years) attending upper secondary schools in 4 Italian regions between September 2021 and May 2023. In the participating regions, an attempt was made to involve 2 schools to be subjected screening and 4 control schools, with a 1:2 ratio between cases and controls. The enrollment of students occurred on a voluntary basis by signing an informed consent.
The screening involved the execution of repeated tests, performed on rotation every 15 days, through the use of salivary molecular tests. The registration of positive cases notified by the control schools took place via a dedicated application.
They were 16 experimental and 32 control schools were enrolled, with 2,527 students actively screened and 29,228 control students (total enrolled in schools). Among participating students, 2,348 recorded at least one valid swab for analysis, with an average of approximately 5 swabs per subject. The experimental arm saw the administration of 11,475 total swabs, of which 9,177 were valid for analysis, with a loss of 20% of tests. Of the swabs valid over the entire two-year period, 89 (3.5%) tested positive. In the control schools, the positive cases detected represented 6.5% of the total enrolled students (N=1,895). Peaks of infection were recorded in the winter months and in the autumn period of reopening of schools, a similar result to what was found in the general population. A progressive decrease in participation in active screening (case schools) was detected, with the number of participants increasing from 2,233 in the school year. 2021-2022 at 294 in the school year 2022-2023. If in the two-year study period the control schools always record a greater number of positives, in December 2022 a reversal occurs, with the 2.6% of positives in case schools against it 0.3% in control schools.
Figure 1. COVID-19 cases reported in case and control schools. September 2021-May 2023
The limitations that emerge from the study show how the voluntariness underlying participation in the screening plan has significantly reduced participation in active screening (case schools). This is demonstrated by the number of memberships, which went from 2,233 during the 2021-2022 school year to only 294 in the 2022-2023 school year.
As proof of this, it is highlighted that in the first part of the study, the control schools always record a greater number of positive cases than those intercepted by active screening conducted in the case schools.
However, once the emergency phase of the pandemic has been overcome and the surveillance tools for the general population have been abolished (e.g. DAD, green pass, etc.), the screening shows its effectiveness in the early identification of asymptomatic cases of COVID-19 by highlighting how, despite the poor adherence of the student population, the circulation of the virus was still present.
By:
» Caterina Milli – ARS Toscana
