Effect of changing case definitions for COVID-19 on the epidemic curve and transmission parameters in mainland China: a modelling study
Effect of changing case definitions for COVID-19 on the epidemic curve and transmission parameters in mainland China: a modelling study
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DOI：
10.1016/s2468-2667(20)30089-x
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发表时间：
2020-05-01
影响因子：
50
通讯作者：
Cowling, Benjamin J.
中科院分区：
文献类型：
--
作者：
Tsang, Tim K.;Wu, Peng;Cowling, Benjamin J.
背景当新的传染病出现时，适当的病例定义对于临床诊断和公共卫生监测很重要。随着时间的推移跟踪案例数对于建立传播速度和干预措施的有效性很重要。我们的目的是评估案例定义的变化是否影响了中国冠状病毒疾病的传播动态的推论。在第一次流行病浪潮中，我们检查了中国大陆的案例定义的方法。我们使用指数增长模型来估计案例定义的变化如何影响每天报告的病例数。然后，我们推断，如果在整个流行病中使用了相同的案例定义，那么流行病曲线将如何出现。从1月15日至3月3日，2020年3月3日，国家卫生委员会在COVID-19的案件定义的七个版本中。中国。我们估计，当案例定义更改时，从版本1到2，2.8倍（1。9），随着病例增加了7.1倍（95％可信间隔[CRI]4。8-10。9）的感染比例（95％的可信间隔[CRI]4。8-10。9）（1。 -4。到2020年2月20日，将有232 000（95％CRI 161 000-359 000）在中国确认的案件，而不是报告的55 508案件。随着知识的增加，尤其是温和的病例以及与武汉，中国或其他已知病例没有流行病学联系的病例，发现更多病例。在推断流行病的增长率和加倍时间（因此对生殖数量）时，应考虑这些变化，以避免偏见。版权（c）2020作者。由Elsevier Ltd发表。这是CC BY-NC-ND 4.0许可下的开放式访问文章。
Background When a new infectious disease emerges, appropriate case definitions are important for clinical diagnosis and for public health surveillance. Tracking case numbers over time is important to establish the speed of spread and the effectiveness of interventions. We aimed to assess whether changes in case definitions affected inferences on the transmission dynamics of coronavirus disease 2019 (COVID-19) in China.Methods We examined changes in the case definition for COVID-19 in mainland China during the first epidemic wave. We used exponential growth models to estimate how changes in the case definitions affected the number of cases reported each day. We then inferred how the epidemic curve would have appeared if the same case definition had been used throughout the epidemic.Findings From Jan 15 to March 3, 2020, seven versions of the case definition for COVID-19 were issued by the National Health Commission in China. We estimated that when the case definitions were changed, the proportion of infections being detected as cases increased by 7.1 times (95% credible interval [CrI] 4. 8-10. 9) from version 1 to 2, 2.8 times (1. 9-4. 2) from version 2 to 4, and 4.2 times (2.6-7.3) from version 4 to 5. If the fifth version of the case definition had been applied throughout the outbreak with sufficient testing capacity, we estimated that by Feb 20, 2020, there would have been 232 000 (95% CrI 161 000-359 000) confirmed cases in China as opposed to the 55 508 confirmed cases reported.Interpretation The case definition was initially narrow and was gradually broadened to allow detection of more cases as knowledge increased, particularly milder cases and those without epidemiological links to Wuhan, China, or other known cases. These changes should be taken into account when making inferences on epidemic growth rates and doubling times, and therefore on the reproductive number, to avoid bias. Copyright (C) 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license.