Analysis of the time evolution of SARS-CoV-2 lethality rate in Italy: Evidence of an unaltered virus potency

Abstract

In recent months, the entire world is facing a dramatic health emergency caused by the diffusion of a hitherto unknown coronavirus (SARS-CoV-2). Despite the efforts, the understanding of the many facets of the pandemic is still rather limited. In the present manuscript, we have monitored the evolution of the lethality rate in Italy by using the data collected over the last three months. Our data indicate that there is a striking correlation between the number of infected people of a certain week and the deaths of the following one. Despite the overall simplicity of the applied approach and its many approximations, the analysis of the Italian scenario provides some interesting insights into the pandemic. Indeed, we have found that the lethality rate is virtually unchanged over the last two months. This implies that the reduction of the deaths is strictly connected to the decrease of cases. Unfortunately, the present study does not support the idea that the virus potency has lowered in the last weeks, as our data demonstrate that the likelihood of a fatal outcome after the infection has not decreased in the recent outbreak evolution. Moreover, we show that the lethality rate is still very high in the country (≈13.5%). Since this number is remarkably higher if compared to the actual lethality estimates made worldwide, this finding suggests that the number of detected cases may be a gross underestimation of the actual infected people, likely due to the presence of a significant number of non-symptomatic or paucisymptomatic individuals in the population.

The temporal correlation between positive testing and death in Italy: from the first phase to the later evolution of the COVID-19 pandemic

“…Following our previous study of the time evolution of COVID-19 lethality during the first wave (8,9), our analysis included:…”

“…In this scenario, the gathering of information on the burden of the disease is of utmost importance for better understanding the origin and evolution of the pandemic spreading and the effectiveness of the public health interventions (3). By analyzing the evolution of the pandemic outbreak in Italy, the center of the first main outbreak among Western countries, we have recently examined the temporal correlation between the positive testing to COVID-19 and deaths in the first phase, i.e., the period March-June 2020 (8,9). In particular, we found, on average, a one-week delay between the positive test and the fatal event.…”