Nationwide analysis of COVID-19 death rate throughout the pandemic in Italy

Background: No definitive epidemiological evidence is available on SARS-CoV-2 lethality during the surge of different variants of concern (VoCs) and coronavirus disease 2019 (COVID-19) vaccination in relation to common flu fatality. Methods: We collected and longitudinally analyzed official data about new COVID-19 cases and COVID-9 related deaths throughout the pandemic in Italy, which were then compared with the recent influenza virus-related fatality rate. Results: The mortality rate of COVID-19 has declined from 3.53% during predominance of the ancestral SARS-CoV-2 strain to 0.26–0.21% after surge of the new Omicron sublineages BA.1/2 and BA.4/5, when the nationwide COVID-19 vaccine coverage with primary cycle and booster doses has been concomitantly extended to 90.2% and 84.5% of the general population aged ≥12 years, respectively. The death rate of COVID-19 was approximately 11-fold higher than that of common flu (i.e., 3.53% versus 0.32%) at the beginning of the pandemic, but has then become 36% lower than that caused by the Influenza virus after widespread COVID-19 vaccine coverage, acquisition of natural immunity and surge of Omicron sublineages BA.4/5. Conclusions: Although our findings underpin a reassuring epidemiological scenario, with death rate of COVID-19 currently lower than that of Influenza virus in Italy, we reemphasize the importance of preventing further surge of aggressiveness (and potential lethality) of SARS-CoV-2, especially in the most vulnerable parts of the population.