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Prevalence of SARS-CoV-2 variants in Italy (ISS Report n. 31 and April 4th 2023 ISS Flash Survey)

Prevalence of SARS-CoV-2 variants of concern in Italy, according to the 31st genomic surveillance Report and the Flash Survey of April 4th 2023 by ISS (data published by ISS on April 14th and May 2nd 2023)

Published: 19 May 2023

By periodic analysis of the data processed through I-Co-Gen, the Italian National Institute of Health (ISS), supported by the Bruno Kessler Foundation and in collaboration 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 last report (April 4th 2023). Data from the previous report (March 7th 2023) are also included for the sake of comparison.
Prevalence of SARS-CoV-2 variants in Italy (ISS Report n. 31 and April 4th 2023 ISS Flash Survey)
The table reports the prevalence of Omicron variant lineages and sublineages (B.1.1.529, derivative lineages and recombinant lineages) of SARS-CoV-2. Currently, Omicron is the only variant of the virus circulating in Italy and worldwide. For this reason the World Health Organisation (WHO) recently revised its variants classification system in order to independently evaluate the large amount of Omicron descending lineages. Additional information concerning the novel nomenclature of variants can be found here, in an official statement by WHO.
Data are aggregated by Region/Autonomous Province and the total number of genome sequences considered in the analysis is reported as well. Aggregated data are also reported to present an overview of the current situation in Italy.
Matched data from the previous report (March 7th 2023) are included for the sake of comparison.

According to data collected during the April 4th 2023 Flash Survey and available in the Report n. 31 by ISS the group of lineages identified as XBB (Omicron/Omicron recombinants) is the most widespread family of lineages in Italy with a prevalence at national level equal to 76,4%. The number of XBB sublineages identified in Italy increased and it’s now equal to 62 sublineages (previously 17); XBB.1.5 (a recombinant of BJ.1 and BA.2.75 with an additional F486P Spike mutation) is the most widespread. In fact, the prevalence of XBB.1.5 increased from 38,4% to 45,3% between March 7th and April 4th 2023. The highest prevalence (66,7%) is observed in Liguria and PA Bolzano, while the lowest (0,0%) in Basilicata. The second most frequent XBB lineage is XBB.1.9.1, with a prevalence of 14.5%.
The prevalence of lineages from the BQ.1 family (a group of BA.5 sublineages) decreased with respect to the last update (March 7th 2023, Report n. 30) from 29,6% to 9,7% (April 4th 2023, Report n. 31).
Finally, the circulation of the BA.2.75 decreased as well and its national prevalence was reduced from 12,0% in the previous update (March 7th 2023) to 6,3% on April 4th 2023.

It is important to remark, however, that the number of genomes sequenced during the April 4th 2023 Flash Survey (584 sequences in total) could be inadequate to correctly estimate the prevalence of the different variants circulating in Italy.

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):

Source: ISS (prevalence data)