Background: Since SARS-CoV-2 has undergone a considerable genetic evolution over time, we investigated its infectivity in the province of Verona (Italy), during the month of July of the first three pandemic years (i.e., 2020, 2021 and 2022).
Methods: The daily number of new COVID-19 diagnoses in the province of Verona between July 1-27 of the years 2020, 2021 and 2022 was retrieved from the database of the Regional Healthcare Service, whilst the mean daily air temperature during the same period in the same area was downloaded from an official Italian meteorological website.
Results: The mean July air temperature in Verona was 24±2°C in 2020, 25±2°C in 2021 and 28±2°C in 2022. The daily number of new COVID-19 diagnoses in the province of Verona increased from 2.5±5.7 in July 2020, to 106.0±71.8 in July 2021, up to 1287.4±509.9 in July 2022. The number of new COVID-19 diagnoses made in the province of Verona in July 2022 has increased by 519- and 12-fold in 2022 compared to the same month of the previous two years, despite the fact that the mean air temperature also notably increased by 18% and 15% compared to the years 2020 and 2021, respectively.
Conclusion: The results of this analysis suggest that the strong evolutive pressure placed on SARS-CoV-2 over time may have fostered the accumulation of mutations that have contributed to evolve and adapt the virus to circulate even at high temperatures, thus calling for reinforcing preventive measures and healthcare preparedness even during the warmest periods of the year.