1.
Preprint
in English
| medRxiv
| ID: ppmedrxiv-22269949
ABSTRACT
The SARS-CoV-2 variant of concern Omicron was first detected in Italy in November 2021. Data from three genomic surveys conducted in Italy between December 2021 and January 2022 suggest that Omicron became dominant in less than one month (prevalence on January 3: 78.6%-83.8%) with a doubling time of 2.7-3.1 days. The mean net reproduction number rose from about 1.15 in absence of Omicron to a peak of 1.83 for symptomatic cases and 1.33 for hospitalized cases, while it remained stable for critical cases.