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The following is a summary of “Integrated analyses of the transmission history of SARS-CoV-2 and its association with molecular evolution of the virus underlining the pandemic outbreaks in Italy, 2019-2023,” published in the December 2024 issue of Infectious Disease by Cella et al.
Italy faced an adverse impact from the COVID-19 pandemic, with multiple infection waves driven by emerging SARS-CoV-2 variants.
Researchers conducted a retrospective study analyzing viral genome sequences and integrating epidemiological and phylodynamic approaches to characterize the spread of SARS-CoV-2 variants in Italy.
They retrieved all full-length Italian viral genomes from GISAID until December 31, 2023. Sequence quality was assessed using NextClade, excluding incomplete or problematic data, to ensure accuracy. To account for regional sequencing variations and accurately represent variant prevalence, an Italy-specific and global subsampling methods were applied. The subsampler method was employed to select sequences based on case counts, ensuring geographic, temporal, and epidemiological representation.
The results showed bidirectional international transmission of SARS-CoV-2, with Italy shifting between importing and exporting the virus, 4 distinct epidemic waves emerged in Italy from 2021 to 2023, each marked by a drop in fatalities. These waves were primarily driven by the emergence of variants of concern (VOCs), such as Alpha, Delta, and Omicron, influencing transmission dynamics and the effectiveness of public health measures.
Investigators concluded the growing viral spread and variant prevalence in Italy emphasized the need for adaptable public health strategies and genomic surveillance to manage future outbreaks.
Source: sciencedirect.com/science/article/pii/S1201971224003333#sec0002
