Tracking the progressive spread of the SARS-CoV-2 Omicron variant in Italy, December 2021 to January 2022 Stefanelli, Paola and Trentini, Filippo and Petrone, Daniele and Mammone, Alessia and Ambrosio, Luigina and Manica, Mattia and Guzzetta, Giorgio and d'Andrea, Valeria and Marziano, Valentina and Zardini, Agnese and Molina Grane’, Carla and Ajelli, Marco and Di Martino, Angela and Riccardo, Flavia and Bella, Antonino and Sane Schepisi, Monica and Maraglino, Francesco and Poletti, Piero and Palamara, Anna Teresa and Brusaferro, Silvio and Rezza, Giovanni and Pezzotti, Patrizio and Merler, Stefano and the Genomic SARS–CoV–2 National Surveillance Working Group and the Italian Integrated Surveillance of COVID–19 Study Group, Eurosurveillance, 27, 2200125 (2022), https://doi.org/10.2807/1560-7917.ES.2022.27.45.2200125