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Prevalence of SARS-CoV-2 variants in Italy (ISS Report n. 25 and October 4th 2022 ISS Flash Survey)

Prevalence of variants of concern of SARS-CoV-2 in Italy, according to the 25th ISS genomic surveillance report and the ISS Flash Survey of October 4th 2022

Published: 02 December 2022


The I-Co-Gen platform by the Italian National Institute of Health (ISS) is the reference point for the collection and analysis of SARS-CoV-2 genome sequencing data in Italy. By periodic analysis of the data processed through I-Co-Gen, the Italian National Institute of Health (ISS), in collaboration with the Bruno Kessler Foundation and with the Italian Ministry of Health, the Regional administrations and the Autonomous Provinces (PPAA), have undertaken a coordinated effort to monitor the spread of SARS-CoV-2 variants in Italy. Data are released periodically in the form of brief reports (further details here, Italian only).
This highlight provides a brief overview of the main results from the most recent report (October 4th 2022). Data from the previous report (September 6th 2022) are also included for the sake of comparison.
Prevalence of SARS-CoV-2 variants in Italy (ISS Report n. 25 and October 4th 2022 ISS Flash Survey)
The table reports the prevalence of the Omicron (B.1.1.529, derivative lineages BA.n and recombinant lineages) Variant of Concern (VOC) of SARS-CoV-2 in Italy. Additional information concerning the nomenclature and genomic features of this and other variants can be found here, in a paper by the World Health Organization (WHO).
Data are aggregated by Region/Autonomous Province and the total number of genome sequences considered in the analysis is reported as well. Cumulative data are also reported to present an overview of the current situation in Italy.
Matched data from the previous report (September 6th 2022) are included.

According to data collected during the October 4th Flash Survey performed by ISS, the Omicron variant (B.1.1.529, its derivative lineages BA.n and recombinant lineages) remains the only SARS-CoV-2 variant currently circulating in Italy, with an estimated prevalence of 100,0% at National level.
BA.5 is the most prevalent among Omicron sublineages as its prevalence equals to 93,01% on Italian territory and is above 75,0% in every Region/PPAA analysed.
Moreover, a slight increase in the prevalence of BA.2 from 1,11% in the previous update (genomic data from September 6th 2022) to 2,33% in the current update (genomic data from October 4th 2022) is observed. In particular we witness an increase in the number of genomic sequences assigned to BA.2.75 (and sublineages). This Omicron sublineage is under international monitoring as it presents mutations that could increase immune escape ability and increase ACE2 affinity [1,2].
Finally, no significant variation in the prevalence of BA.4, which is equal to 4,27%, is observed.

Please refer to the report as provided on the ISS website at the following links (italian only) for a complete reference:

The previous report is available at the following link (italian only):

Sources:
ISS (prevalence data),
[1] “Omicron sublineage BA.2.75.2 exhibits extensive escape from neutralising antibodies”. Daniel J. Sheward et al. November 2022,
[2] “Antigenic characterization of the SARS-CoV-2 Omicron subvariant BA.2.75”. QianWang et al. 9 November 2022