1 Department of Pediatrics, Infectious Diseases Unit, Regina Margherita Children' s Hospital, University of Turin, Piazza Polonia 94, Turin, 10126, Italy. marco.denina@gmail.com.
2 Department of Pediatrics, Infectious Diseases Unit, Regina Margherita Children' s Hospital, University of Turin, Piazza Polonia 94, Turin, 10126, Italy.
3 Department of Virology and Microbiology, A.O. Città della Salute e della Scienza (Molinette), University of Turin, Turin, Italy.