Suppression of a SARS-CoV-2 outbreak in the Italian municipality of Vo'
Suppression of a SARS-CoV-2 outbreak in the Italian municipality of Vo'
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DOI：
10.1038/s41586-020-2488-1
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发表时间：
2020-06-30
期刊：
影响因子：
64.8
通讯作者：
Crisanti, Andrea
中科院分区：
文献类型：
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作者：
Lavezzo, Enrico;Franchin, Elisa;Crisanti, Andrea
2020年2月21日，意大利帕多瓦（意大利）附近小镇沃市的一名居民，死于严重急性呼吸道综合征冠状病毒2型（SARS-CoV-2）感染肺炎（1）。这是自中国湖北省武汉市检测到SARS-CoV-2以来，意大利检测到的首例冠状病毒疾病19（COVID-19）相关死亡病例（2）。作为回应，地方当局对整个城市实施了14天的封锁（3）。在这里，我们收集了人口统计学，临床表现，住院，接触网络和存在的SARS-CoV-2感染的鼻咽拭子中的85.9%和71.5%的Vo'人口在两个连续的时间点的信息。第一次调查是在城镇封锁开始时进行的，我们发现感染率为2.6%（95%置信区间（CI）：2.1-3.3%）。第二次调查是在封锁结束时进行的，我们发现患病率为1.2%（95% CI：0.8-1.8%）。值得注意的是，在两次调查中发现的确诊SARS-CoV-2感染者中，有42.5%（95% CI：31.5-54.6%）无症状（即在拭子检测时没有症状，之后也没有出现症状）。平均连续间隔为7.2天（95% CI：5.9-9.6）。我们发现有症状感染者与无症状感染者的病毒载量无统计学显著性差异（E和RdRp基因的精确Wilcoxon-Mann-Whitney检验分别为P= 0.62和0.74）。这项研究揭示了无症状SARS-CoV-2感染的频率，其传染性（通过病毒载量测量），并提供了对其传播动力学和实施控制措施的有效性的见解。
The authors describe the prevalence of SARS-CoV-2 infection, viral load and the frequency of symptomatic versus asymptomatic and presymptomatic infection in an Italian town, before and after a strict 14-day lockdown.On 21 February 2020, a resident of the municipality of Vo', a small town near Padua (Italy), died of pneumonia due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection(1). This was the first coronavirus disease 19 (COVID-19)-related death detected in Italy since the detection of SARS-CoV-2 in the Chinese city of Wuhan, Hubei province(2). In response, the regional authorities imposed the lockdown of the whole municipality for 14 days(3). Here we collected information on the demography, clinical presentation, hospitalization, contact network and the presence of SARS-CoV-2 infection in nasopharyngeal swabs for 85.9% and 71.5% of the population of Vo' at two consecutive time points. From the first survey, which was conducted around the time the town lockdown started, we found a prevalence of infection of 2.6% (95% confidence interval (CI): 2.1-3.3%). From the second survey, which was conducted at the end of the lockdown, we found a prevalence of 1.2% (95% CI: 0.8-1.8%). Notably, 42.5% (95% CI: 31.5-54.6%) of the confirmed SARS-CoV-2 infections detected across the two surveys were asymptomatic (that is, did not have symptoms at the time of swab testing and did not develop symptoms afterwards). The mean serial interval was 7.2 days (95% CI: 5.9-9.6). We found no statistically significant difference in the viral load of symptomatic versus asymptomatic infections (P= 0.62 and 0.74 forEandRdRpgenes, respectively, exact Wilcoxon-Mann-Whitney test). This study sheds light on the frequency of asymptomatic SARS-CoV-2 infection, their infectivity (as measured by the viral load) and provides insights into its transmission dynamics and the efficacy of the implemented control measures.