2.2-Viral diagnostic testing
Respiratory specimens were obtained from children within the first 48 hours after the admission and transported to the laboratory in a viral transport medium (UTM, Copan Diagnostics, Italy). The automated nucleic acid extraction was performed according to the manufacturer’s recommendations using the EZ1 Virus Mini Kit v2 (Qiagen, Luxembourg). The RT-PCR conducted on the Rotor-Gene device (Qiagen) with the FTD® Respiratory Pathogens 21 Kit (Luxemburg) was used to detect respiratory viruses (RSV-A/B, influenza-A/B, HRV, human coronavirus [hCoV] NL63/229E/OC43/HKU1, PIV1-4, HMPV-A/B, HBoV, human adenovirus [HAdV], human enterovirus [EV], and human parechovirus). The kits and results obtained were tested using the National External Quality Assurance Schemes (NEQUAS) External Quality Control program (NEQUAS, Scotland).