Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Section of Public Health, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
Head Office, Direzione Generale, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy.
Acta Biomed. 2021 Oct 1;92(S6):e2021420. doi: 10.23750/abm.v92iS6.12241.
The exact COVID-19 severity is still not well defined and it is hotly debated due to the a few methodological issues such as the uncertainties about the spread of the SARS-CoV-2 infection.
We investigated COVID-19 case-fatality rate and infection-fatality rate in 2020 in Italy, a country severely affected by the pandemic, basing our assessment on publicly available data, and calculating such measures during the first and second waves.
We found that province-specific crude case-fatality rate in the first wave (February-July 2020) had a median value of 12.0%. Data about infection-fatality rate was more difficult to compute, due to large underestimation of SARS-CoV-2 infection during the first wave when asymptomatic individuals were very rarely tested. However, when using as a reference population-based seroprevalence data for anti-SARS-CoV-2 antibodies collected in May-July 2020, we computed an infection-fatality rate of 2.2%. During the second wave (Sep-Dec 2020), when SARS-CoV-2 testing was greatly increased and extended to many asymptomatic individuals, we could only compute a 'hybrid' case/infection-fatality rate with a value of 2.2%, similar to the infection-fatality rate of the first wave.
Overall, this study allowed to assess the COVID-19 case- and infection-fatality rates in Italy before of variant spread and vaccine availability, confirming their high values compared with other airborne infections like influenza. Our findings for Italy were similar to those characterizing other Western European countries.
由于一些方法学问题，如对 SARS-CoV-2 感染传播的不确定性，COVID-19 的严重程度仍未得到很好的定义，并且存在激烈的争论。
我们调查了意大利 2020 年 COVID-19 的病死率和感染病死率，意大利是一个受大流行严重影响的国家，我们的评估基于公开数据，并在第一波和第二波疫情期间计算了这些指标。
我们发现，在第一波疫情（2020 年 2 月至 7 月）中，各省的粗病死率中位数为 12.0%。由于在第一波疫情期间，无症状者很少接受检测，因此很难计算感染病死率的数据，这导致了对 SARS-CoV-2 感染的严重低估。然而，当使用 2020 年 5 月至 7 月收集的基于人群的抗 SARS-CoV-2 抗体血清阳性率数据作为参考时，我们计算出的感染病死率为 2.2%。在第二波疫情（2020 年 9 月至 12 月）期间，由于 SARS-CoV-2 检测大大增加并扩展到许多无症状者，我们只能计算出一个“混合”的病例/感染病死率，其值为 2.2%，与第一波疫情的感染病死率相似。
总的来说，这项研究评估了意大利在变异株传播和疫苗可获得性之前的 COVID-19 病例和感染病死率，证实了它们与流感等其他空气传播感染相比，其数值较高。我们在意大利的发现与其他西欧国家的发现相似。
