Acknowledgements
We gratefully acknowledge the Collaborator Members of ISS COVID-19 study group: Angela Di Martino, Marzia Facchini, Fabiola Mancini, Simona Puzelli, Giuseppina Di Mario, Laura Calzoletti, Stefano Fontana, Giulietta Venturi, Claudia Fortuna, Giulia Marsili, Antonello Amendola, Fabrizio Barbanti, Maria Scaturro, Daniela Fortini, Marco Di Luca, Luciano Toma, Francesco Severini, Patrizio Pezzotti, Antonino Bella, Flavia Riccardo, dept. of Infectious Diseases, Istituto Superiore di Sanità.
We gratefully acknowledge the Authors, the Originating and Submitting Laboratories for their sequence and metadata shared through GISAID and NCBI, on which this research is based. All submitters of data may be contacted directly via www.gisaid.org. The Acknowledgments Table for GISAID and NCBI is reported as Supplementary material.
The authors also thank Davide Mileto, Alessandro Mancon, Clinical Microbiology, Virology and Bioemergency, L. Sacco University Hospital, Milan, Italy and Concetta Castilletti, Eleonora Lalle, Francesca Colavita, Fabrizio Carletti, Daniele Lapa, Licia Bordi Laboratory of Virology, National Institute for Infectious Diseases “Lazzaro Spallanzani” IRCCS, Rome, Italy, for performing diagnostic SARS-Cov-2 tests.
Disclaimer: The new sequences have been deposited in GISAID with accession IDs: EPI_ISL_412973 and 412974.

Conflict of interest: None declared.
Authors’ contributions: PS: conceived the study, coordinated the in vitro virus cultivation and wrote the manuscript together with FL and ALP; SFiore, EB,AM,CF prepared the Vero cells and cultivated the two virus; GF, AF, RDS and SFillo performed the whole genome sequence of the new genomes (ID: EPI_ISL_412973 and 412974); ALP, AA, AC analysed the genomes together with GF and FL; MRCapobianchi and MRG diagnosed SARS-CoV-2 onto the two samples; AC set up the molecular methods; MRCastrucci coordinated laboratory confirmation; GR read and revised the manuscript. The authors read and approved the manuscript.

Supplementary Data
Supplementary Material
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