  Several epidemiological models have been proposed to study the evolution of
COVID-19 pandemic. In this paper, we propose an extension of the SUIHTER model,
first introduced in [Parolini et al, Proc R. Soc. A., 2021] to analyse the
COVID-19 spreading in Italy, which accounts for the vaccination campaign and
the presence of new variants when they become dominant. In particular, the
specific features of the variants (e.g. their increased transmission rate) and
vaccines (e.g. their efficacy to prevent transmission, hospitalization and
death) are modeled, based on clinical evidence. The new model is validated
comparing its near-future forecast capabilities with other epidemiological
models and exploring different scenario analyses.
