论文标题
使用全因死亡率来稳健地估算意大利北部的Covid19流行曲线
Robustly estimating the COVID19 epidemic curve in northern Italy using all-cause mortality
论文作者
论文摘要
背景：意大利北部是Covid受影响最大的地区之一。现在，人们广泛认为该病毒在鉴定出第一位患者之前至少静静地扩散了2周。在这个无声阶段，在接下来的几周内，医院系统过负担过负担时，数据收集没有以足够的方式进行估计流行曲线。为了评估引入病毒引入的动力学和引入遏制措施的有效性，我们尝试使用所有导致死亡率数据重建流行曲线。方法：我们收集了所有导致根据国家统计研究所年龄分层的死亡率数据，以及其他政府结构发布的与COVID相关的死亡数据。使用SEIR模型以及对死亡时间分布的暴露估计，我们将繁殖数在区域层面的不同阶段拟合。结果：我们估计鉴定情况1之前的繁殖数为2.6 +/- 0.1。 Lombardy的学校关闭将其降低到1.3。软锁定度量导致R <0.8，并且当引入硬锁定时未观察到进一步的减少（例如，艾米利亚 - 罗马尼亚软锁定0.67 +/- 0.07，硬锁定0.69 +/- 0.071）。硬锁定期间> 75岁范围的繁殖数量始终高于其他人口（例如0.98 vs 0.71在米兰省），这表明退休设施爆发。从3月7日起，伯加莫和布雷西亚省的繁殖数量明显低于其他具有相同严格锁定措施的地区（附近的省份：0.73：0.73，布雷西亚：0.52：0.52，Bergamo 0.43），这是支持这一假设的，即在3月开始，在这些省份中已经很大一部分人口已经感染了这些省份。
Background: Northern Italy was one of the most impacted areas by COVID. It is now widely assumed that the virus was silently spreading for at least 2 weeks before the first patient was identified. During this silent phase, and in the following weeks when the hospital system was overburdened, data collection was not performed in an accurate enough way to estimate an epidemic curve. With the aim of assessing both the dynamics of the introduction of the virus and the effectiveness of containment measures introduced, we try to reconstruct the epidemic curve using all cause mortality data. Methods: we collected all cause mortality data stratified by age from the national institute of statistics, together with COVID-related deaths data released by other government structures. Using a SEIR model together with estimates of the exposure to death time distribution, we fitted the reproduction number in different phases of the spread at regional level. Results: We estimate a reproduction number of 2.6+/-0.1 before case 1 was identified. School closures in Lombardy lowered it to 1.3. Soft lockdown measures resulted in R<0.8 and no further reductions were observed when a hard lockdown was introduced (e.g. Emilia-Romagna soft lockdown 0.67 +/-0.07, hard lockdown 0.69+/-0.071). Reproduction number for the >75 age range during hard lockdown are consistently higher than for the rest of the population (e.g. 0.98 vs 0.71 in Milan province), suggesting outbreaks in retirement facilities. Reproduction numbers in Bergamo and Brescia provinces starting from March 7th are markedly lower than in other areas with the same strict lockdown measures (Nearby provinces: 0.73, Brescia: 0.52, Bergamo 0.43) supporting the hypothesis that in those provinces a large percentage of the population had already been infected by the beginning of March.
