Press Release N°39/2021 COVID-19: In the last 45 days, 69.2% of sequenced swabs were positive for the Delta variant

In Italy, in the last 45 days, 69.2% of sequenced swabs tested positive for the delta variant, thus taking over the alpha variant which has stopped at 17.3%. New cases of infection caused by the Delta variant have been reported in all Regions / Autonomous Provinces. The data are contained in the sixth ISS Newsletter "Prevalence and distribution of SARS-CoV-2 variants of interest for public health in Italy",and are confirmed by the data of the flash survey which reported data referring only to 20 May.

6.6% of the Sars-CoV-2 positive swabs were sequenced in July. The platform for the genomic surveillance of the SARS-oV-2 (I-Co-Gen) variants, developed and coordinated by the Istituto Superiore di Sanità, ISS (Italian National Institute of Health), has been active since 29 April 2021. The module, dedicated to analysing and sharing SARS-CoV-2 sequencing data nationwide, counts more than 21,000 sequences. The percentage of sequences attributable to the Delta variant, out of the total sequences deposited with I-Co-Gen, was 2.09% in April, 7.48% in May, 40.15% in June, 85.66% in July (data as at August 2, 2021) with weekly increases within the same month.

The main conclusions

- In the last 45 days, new cases of infection caused by the Delta variant have been reported in all Regions / Autonomous Provinces. Cases of infection caused by the Delta variant have been observed in all age groups, with a higher percentage of cases in individuals aged between 10 and 29 years.

- The frequency of cases caused by the Alpha variant is strongly decreasing, while its territorial diffusion remains stable.

- Also the frequency of cases caused by the Gamma variant (lineage P.1) of the SARS-CoV-2 virus is decreasing, with a greater diffusion in some Italian Regions / Autonomous Provinces.