1. These authors contributed equally to this work and share first authorship
2. Microbiology and Virology Department, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
3. Neonatal Intensive Care Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
4. Department of Clinical, Surgical, Diagnostic and Paediatric Sciences, University of Pavia, Pavia, Italy
5. Paediatric Intensive Care Unit, Ospedale Papa Giovanni XXIII, Bergamo, Italy
6. These authors contributed equally to the work and share the last authorship