Press Release No. 70/2022 COVID19: ISS Flash Survey, 100% Omicron on 4 October, Subvariant BA.5 was predominant, while BA.4, BA.2 and BA.1 were also present

In Italy on 4 October, the Omicron variant had an estimated prevalence of 100%, with the subvariant BA.5 being largely predominant while a small increase was reported for the BA.2 variant compared to the previous report (2.3% vs. 1.1%). These are the results of the flash survey carried out by the ISS and the Ministry of Health together with the regional laboratories and the Bruno Kessler Foundation.

For the survey, the laboratories of the Regions and Autonomous Provinces were asked to select subsamples of positive cases and to sequence the genome of the virus. The requested samples were subsequently selected randomly by the Regions/PPAAs from among the positive samples ensuring some degree of geographical representativeness and, where possible, representation of the different age groups. In total, 20 Regions/PPAAs participated in the survey for a total of 100 regional laboratories alongside the Military Health Laboratory and a total of 1557 samples processed.

These are the estimated prevalences:

BA.1 0.1% (range: 0%  - 2.3%)

BA.2 2.3% (range: 0% - 6.3%)

BA 4 4.3% (range: 0%  - 25.0%)

BA 5 93.0% (range: 75.0% - 100.0%)

Other 0.3% (range 0%-1.9%)