Data collection
The present paper describes a cross-sectional study performed between 14th September 2020 and 18th March 2021 among a sample of 13,283 paediatric patients (aged 0-19 years) who underwent a swab at OIRM in four different hospital settings (HS, Emergency department, DH setting and hospital wards). The data collection ended on 18th March because the number of daily swabs had been significantly reduced due to the improvement of the epidemiological situation of SARS-CoV-2 infections. Hospital wards include COVID-19 ward where positive COVID-19 paediatric patients were hospitalized. Each record represented a unique patient as we considered only the first swab performed at the OIRM for each patient.
Two types of test on nasopharyngeal swabs were analysed: nucleic acid amplification test (NAAT), also called molecular test, and detection of virus-specific antigens by rapid antigen detection tests (RADTs), also called rapid test19.
The data collected included: date of swab execution, type of swab (NAAT or RADTs), execution setting of the swab (HS, emergency department, DH setting and hospital wards, result of the swab (positive, negative or indeterminate), sex and age of the paediatric patients.
Last, since the effective reproductive number (Rt), defined as averages of the number of people infected by a typical case at any given moment, play a central role in tracking infectious disease outbreaks, we recorded, for each swab performed, the mean value of the Rt in the Piedmont region calculated in the 14 days prior to the date of execution of the swab20. The Rt values​​ were collected from the weekly reports of the Italian ministry of health21–23.