Background
The novel coronavirus disease is an ongoing pandemic that started in China in December 2019. The aim of this paper is to provide a detailed overview of the first two years of this pandemic in Italy.
Design and methods
: Using the negative binomial distribution, we estimated the daily incidence of infections from the virus lethality and the resulting deaths (estimated by weighted moving average). We adjusted the daily lethality of the original strain (estimated through national sero-surveys) for age, hazard ratios of virus variants of concern and the cumulative distribution of vaccinated people.
Results
From the 24th of February 2020 to the 28th of February 2022, we estimated 20,833,018 (20,728,924 − 20,937,375) cases distributed over 5 waves. The overall lethality was 0.73% and daily ranged from 2.78% (in the first wave) to 0.15% (in the last one). The first two waves showed the highest daily peaks of deaths (about 710), the last one showed the highest daily peak of infections (220,487). Restriction measures of population mobility strongly slowed the virus’s spread. During the second pandemic year, vaccines prevented 10,000,000 infections and 115,000 deaths.
Conclusion
In the summer, the main mode of transmission was presumably direct contact. A massive test campaign allowed monitoring of the virus’ spread, especially among the younger population. Mobility restriction measures are effective in a suppression strategy; distance learning and smart working are effective in a mitigation strategy. Despite the variants of concern, vaccines strongly reduced the pandemic impact on the healthcare system and avoided strong restriction measures.