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Prevalence of SARS-CoV-2 variants in Italy (ISS Report n. 20 and May 3rd 2022 ISS Flash Survey)

Prevalence of SARS-CoV-2 variants of concern in Italy (according to the 20th ISS genomic surveillance report and the ISS Flash Survey of May 3rd 2022)

Published: 30 May 2022

The I-Co-Gen platform by the Italian National Institute of Health (ISS) is the most up to date system 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), 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. Results 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 (data from May 3rd 2022). Data from the previous report (data from April 4th 2022) are also included for the sake of comparison.
Prevalence of SARS-CoV-2 variants in Italy (ISS Report n. 20 and May 3rd 2022 ISS Flash Survey)
The table reports the prevalence of the Omicron (B.1.1.529, derivative lineages BA.n and BA.1/BA.2 recombinant lineages) Variant of Concern (VOC) of SARS-CoV-2 in Italy. Additional information concerning the nomenclature and genomic features of this kind of variants can be found here, in a paper by the World Health Organization (WHO).
Prevalence data are aggregated by Region/Autonomous Province, the total number of genome sequences included 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 (April 4th 2022) are included.

According to the results of the most recent ISS Flash Survey (May 3rd 2022), the Omicron variant (B.1.1.529, derivative lineages BA.n and BA.1/BA.2 recombinant lineages) is the only variant showing a sustained circulation in Italy, and shows an estimated prevalence of 100% in every Region/PPAA. However, a shift in the prevalence of Omicron sublineages is observed: while BA.1 registered a reduction of its prevalence, which decreased from the 11,8% of April 4th to the 3,52% of May 3rd 2022, the prevalence of BA.2 increased from 86,6% to 93,83%. Thus, the BA.2 sublineage is the most prevalent sublineage of Omicron in Italy. All the other Omicron sublineages show a prevalence below 1%. However it is worth mentioning that these other lineages include BA.1/BA.2 recombinants which, according to guidelines by the World Health Organization (WHO), require close monitoring since their level of risk for public health (both in terms of transmission and severity of the disease) is still largely unknown.

Please refer to the reports 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)