Hsieh Ying-Hen
Department of Public Health and Center for Infectious Disease Education and Research,China Medical University , Taichung , Taiwan.
PeerJ. 2015 Dec 17;3:e1505. doi: 10.7717/peerj.1505. eCollection 2015.
Background. Since the emergence of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in 2012, more than 1,300 laboratory confirmed cases of MERS-CoV infections have been reported in Asia, North Africa, and Europe by July 2015. The recent MERS-CoV nosocomial outbreak in South Korea quickly became the second largest such outbreak with 186 total cases and 36 deaths in a little more than one month, second only to Saudi Arabia in country-specific number of reported cases. Methods. We use a simple mathematical model, the Richards model, to trace the temporal course of the South Korea MERS-CoV outbreak. We pinpoint its outbreak turning point and its transmissibility via basic reproduction number R 0 in order to ascertain the occurrence of this nosocomial outbreak and how it was quickly brought under control. Results. The estimated outbreak turning point of ti = 23.3 days (95% CI [22.6-24.0]), or 23-24 days after the onset date of the index case on May 11, pinpoints June 3-4 as the time of the turning point or the peak incidence for this outbreak by onset date. R 0 is estimated to range between 7.0 and 19.3. Discussion and Conclusion. The turning point of the South Korea MERS-CoV outbreak occurred around May 27-29, when control measures were quickly implemented after laboratory confirmation of the first cluster of nosocomial infections by the index patient. Furthermore, transmissibility of MERS-CoV in the South Korea outbreak was significantly higher than those reported from past MERS-CoV outbreaks in the Middle East, which is attributable to the nosocomial nature of this outbreak. Our estimate of R 0 for the South Korea MERS-CoV nosocomial outbreak further highlights the importance and the risk involved in cluster infections and superspreading events in crowded settings such as hospitals. Similar to the 2003 SARS epidemic, outbreaks of infectious diseases with low community transmissibility like MERS-CoV could still occur initially with large clusters of nosocomial infections, but can be quickly and effectively controlled with timely intervention measures.
背景。自2012年中东呼吸综合征冠状病毒（MERS-CoV）出现以来，截至2015年7月，亚洲、北非和欧洲已报告1300多例实验室确诊的MERS-CoV感染病例。韩国近期发生的MERS-CoV医院内暴发在短短一个多月内迅速成为第二大此类暴发，共186例病例，36人死亡，按国家报告病例数仅次于沙特阿拉伯。方法。我们使用一个简单的数学模型——理查兹模型，来追踪韩国MERS-CoV暴发的时间进程。我们通过基本再生数R0确定其暴发转折点及其传播能力，以确定此次医院内暴发的发生情况以及它是如何迅速得到控制的。结果。估计暴发转折点ti = 23.3天（95%置信区间[22.6 - 24.0]），即5月11日首例病例发病日期后的23 - 24天，按发病日期确定6月3 - 4日为此次暴发的转折点或发病高峰时间。R0估计在7.0至19.3之间。讨论与结论。韩国MERS-CoV暴发的转折点发生在5月27 - 29日左右，当时在首例患者实验室确诊首例医院内感染聚集性病例后迅速实施了控制措施。此外，韩国暴发中MERS-CoV的传播能力明显高于中东过去MERS-CoV暴发报告的传播能力，这归因于此次暴发的医院内性质。我们对韩国MERS-CoV医院内暴发的R0估计进一步凸显了医院等拥挤环境中聚集性感染和超级传播事件的重要性及风险。与2003年非典疫情类似，像MERS-CoV这种社区传播性低的传染病暴发最初仍可能以大量医院内感染聚集性病例出现，但通过及时干预措施可迅速有效控制。
