Using models to identify routes of nosocomial infection: a large hospital outbreak of SARS in Hong Kong
Using models to identify routes of nosocomial infection: a large hospital outbreak of SARS in Hong Kong
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DOI：
10.1098/rspb.2006.0026
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发表时间：
2007-03-07
影响因子：
4.7
通讯作者：
Riley, Steven
中科院分区：
文献类型：
--
作者：
Kwok, Kin On;Leung, Gabriel M.;Riley, Steven
在2002-2003年全球暴发期间，两个因素主导了严重急性呼吸综合征(SARS)的流行病学，即超级传播事件(SSE)和医院感染。虽然这两个因素在香港第一次也是最大规模的医院疫情中都很重要，但不同感染途径的相对重要性尚未得到量化。我们使用SARS发病数据估计了一个新的医院感染数学模型的参数。这些估计描述了指数超级传播者、工作人员和患者之间的传播水平，并被用来比较三种看似合理的假设。支持的最广泛的假设将最初病例的激增归因于单个超级传播的个人，并表明患者的人均感染风险在疫情开始约一个月后增加。我们对SSE导致的病例数量的估计大大低于之前报告的值，这些值大多基于自我报告的暴露信息。这一差异表明，早期将指数病例确定为超级传播者可能导致有偏见的接触者追踪，导致将病例归因于工作人员对工作人员的传播的太少。我们建议，在未来爆发SARS或其他直接传播的呼吸道病原体时，可以使用简单的数学模型来验证关于不同传播途径的相对重要性的初步结论，这对感染控制具有重要意义。
Two factors dominated the epidemiology of severe acute respiratory syndrome (SARS) during the 2002-2003 global outbreak, namely super-spreading events (SSE) and hospital infections. Although both factors were important during the first and the largest hospital outbreak in Hong Kong, the relative importance of different routes of infection has not yet been quantified. We estimated the parameters of a novel mathematical model of hospital infection using SARS episode data. These estimates described levels of transmission between the index super-spreader, staff and patients, and were used to compare three plausible hypotheses. The broadest of the supported hypotheses ascribes the initial surge in cases to a single super-spreading individual and suggests that the per capita risk of infection to patients increased approximately one month after the start of the outbreak. Our estimate for the number of cases caused by the SSE is substantially lower than the previously reported values, which were mostly based on self-reported exposure information. This discrepancy suggests that the early identification of the index case as a super-spreader might have led to biased contact tracing, resulting in too few cases being attributed to staff-to-staff transmission. We propose that in future outbreaks of SARS or other directly transmissible respiratory pathogens, simple mathematical models could be used to validate preliminary conclusions concerning the relative importance of different routes of transmission with important implications for infection control.