COVID-19 outbreak on the Diamond Princess cruise ship: estimating the epidemic potential and effectiveness of public health countermeasures
COVID-19 outbreak on the Diamond Princess cruise ship: estimating the epidemic potential and effectiveness of public health countermeasures
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DOI：
10.1093/jtm/taaa030
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发表时间：
2020-04-01
影响因子：
25.7
通讯作者：
Wilder-Smith, A.
中科院分区：
文献类型：
--
作者：
Rocklov, J.;Sjodin, H.;Wilder-Smith, A.
背景：游轮在相对均匀混合的密闭空间中运载大量人员。2020年2月3日，钻石公主号游轮上报告了COVID-19疫情，最初有10例病例，1月21日至25日左右在船上发现了一例指示病例。截至2月4日，实施了移走和隔离患病旅客以及隔离非患病旅客等公共卫生措施。截至2月20日，3700名乘客和机组人员中619人（17%）检测呈阳性。方法：我们使用SEIR模型估计暴发初期的基本繁殖数。我们用对策的瞬态函数对模型进行校正。此外，我们还估计了在没有对策的情况下的反事实情景，并建立了一个按机组人员和客人分层的模型，以研究群体之间不同接触率的影响。我们还比较了较早和较晚撤离船只的情况。结果：与武汉疫区相比，船上的基本繁殖率最初高出4倍，但采取相应措施后，基本繁殖率大幅降低。根据模型初始值14.8，我们估计，如果在1月21日至2月19日期间不采取任何干预措施，3700人中将有2920人（79%）被感染。隔离隔离预防病例2307例，减少到1.78例。我们表明，2月3日提前疏散所有乘客可能与76名处于潜伏期的感染者有关。结论：游轮条件明显放大了本已高度传播的疾病。与不采取干预措施相比，公共卫生措施预防了2000多例新增病例。然而，在疫情爆发初期疏散所有乘客和机组人员，本可以防止更多乘客和机组人员受到感染。
Background: Cruise ships carry a large number of people in confined spaces with relative homogeneous mixing. On 3 February, 2020, an outbreak of COVID-19 on cruise ship Diamond Princess was reported with 10 initial cases, following an index case on board around 21-25th January. By 4th February, public health measures such as removal and isolation of ill passengers and quarantine of non-ill passengers were implemented. By 20th February, 619 of 3700 passengers and crew (17%) were tested positive.Methods: We estimated the basic reproduction number from the initial period of the outbreak using SEIR models. We calibrated the models with transient functions of countermeasures to incidence data. We additionally estimated a counterfactual scenario in absence of countermeasures, and established a model stratified by crew and guests to study the impact of differential contact rates among the groups. We also compared scenarios of an earlier versus later evacuation of the ship.Results: The basic reproduction rate was initially 4 times higher on-board compared to the in the epicentre in Wuhan, but the countermeasures lowered it substantially. Based on the modeled initial of 14.8, we estimated that without any interventions within the time period of 21 January to 19 February, 2920 out of the 3700 (79%) would have been infected. Isolation and quarantine therefore prevented 2307 cases, and lowered the to 1.78. We showed that an early evacuation of all passengers on 3 February would have been associated with 76 infected persons in their incubation time.Conclusions: The cruise ship conditions clearly amplified an already highly transmissible disease. The public health measures prevented more than 2000 additional cases compared to no interventions. However, evacuating all passengers and crew early on in the outbreak would have prevented many more passengers and crew from infection.