Press Release N°35/2021 COVID-19: in Italy 57.8% of cases are due to the 'Alpha variant', while 22.7% are due to the 'Delta' variant

ISS, July 2nd 2021

In Italy as at June 22, the prevalence of the so-called 'Alpha variant' (B.1.1.7) of SARS-CoV-2 was 57.8%, down from 88.1% on 18 May, with values for the Regions fluctuating between 16.7% and 100%. On the same date, the so-called 'Gamma' variant (P.1) had a prevalence of 11.8% (with a range between 0 and 37.5%, while in the previous survey it was 7.3%). The so-called 'Delta variant' (B.1.167.2) had a prevalence of 22.7% and was identified in 16 Regions / Autonomous Provinces, with a range between 0 and 70.6%. The estimate was made by the new rapid survey carried out by the Istituto Superiore di Sanità – ISS (Italian National Institute of Health) and the Ministry of Health together with the regional laboratories and the Bruno Kessler Foundation. The survey integrates routine monitoring activities, and therefore does not contain all the cases of variants detected but only those detected on the day taken into consideration. The so-called 'K variant', for example, one of the subtypes of B.1.617 (B.1.617.1), was not found in the flash survey, but several cases were reported on the integrated platform which instead collects the analyses day by day.

"The growth in the prevalence of the Delta variant was expected, but it needs to be monitored with great attention”, says ISS president, Silvio Brusaferro. “It is essential to continue the systematic tracking of cases to identify the outbreaks, which at this time is possible given the low incidence, and the vaccination program needs to be completed as quickly as possible, since vaccines ensure the best protection, as confirmed yesterday by the EMA".

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 sample requested was chosen by the Regions / Autonomous Provinces at random from among the positive samples, ensuring geographical coverage and, if possible, representation of the different age groups. In total, 21 Regions / Autonomous Provinces and a total of 113 laboratories participated in the survey, and 772 samples were sequenced - almost all of those eligible for the survey on the chosen day.

These are the main observations that emerged from the survey

● in the Italian context, in which vaccination is in progress but has not yet reached sufficient coverage of all age groups, the spread of variants with greater transmissibility may have a significant impact. While still being predominant, the prevalence of the Alpha variant (B.1.1.7) is decreasing at national level. The survey shows that the prevalence of the Gamma variant (P.1 and its sub-lineages) is increasing slightly compared to the last survey and that the Delta variant (B.1.167.2) is increasing. As regards these data, however, it must be pointed out that the prevalence may be overestimated due to the presence of many outbreaks (which are identified and hence investigated more thoroughly) in the various Italian Regions / Autonomous Provinces;

● in the current European and national scenario, characterized by the circulation of different variants, the spread of the SARS-CoV-2 virus – and in particular the variants having higher transmissibility or with mutations that have strong immune evasion mechanisms - needs to be monitored constantly and carefully, in compliance with national and international recommendations and ministerial indications.

● in order to contain and mitigate the impact of the virus in our Country, it is important to keep the incidence at values that allow both the systematic tracking of most of the positive cases and the massive sequencing of the SARS-CoV-2 virus for the early identification of genetic variants and for curbing their evolution.