Armbruster Benjamin, Brandeau Margaret L
Department of Management Science and Engineering, Stanford University, Stanford, CA 94305-4026, USA.
Math Biosci. 2007 Oct;209(2):386-402. doi: 10.1016/j.mbs.2007.02.007. Epub 2007 Mar 2.
Two common means of controlling infectious diseases are screening and contact tracing. Which should be used, and when? We consider the problem of determining the cheapest mix of screening and contact tracing necessary to achieve a desired endemic prevalence of a disease or to identify a specified number of cases. We perform a partial equilibrium analysis of small-scale interventions, assuming that prevalence is unaffected by the intervention; we develop a full equilibrium analysis where we compare the long-term cost of various combinations of screening and contact tracing needed to achieve a given equilibrium prevalence; and we solve the problem of minimizing the total costs of identifying and treating disease cases plus the cost of untreated disease cases. Our analysis provides several insights. First, contact tracing is only cost effective when prevalence is below a threshold value. This threshold depends on the relative cost per case found by screening versus contact tracing. Second, for a given contact tracing policy, the screening rate needed to achieve a given prevalence or identify a specified number of cases is a decreasing function of disease prevalence. As prevalence increases above the threshold (and contact tracing is discontinued), the screening rate jumps discontinuously to a higher level. Third, these qualitative results hold when we consider unchanged or changed prevalence, and short-term or long-term costs.
控制传染病的两种常见方法是筛查和接触者追踪。应该使用哪种方法，以及何时使用？我们考虑确定实现疾病的期望流行率或识别特定数量病例所需的筛查和接触者追踪的最便宜组合的问题。我们对小规模干预措施进行局部均衡分析，假设流行率不受干预措施影响；我们开展全面均衡分析，比较实现给定均衡流行率所需的各种筛查和接触者追踪组合的长期成本；并且我们解决使识别和治疗病例的总成本加上未治疗病例的成本最小化的问题。我们的分析提供了几个见解。首先，接触者追踪仅在流行率低于阈值时才具有成本效益。该阈值取决于通过筛查与接触者追踪发现的每个病例的相对成本。其次，对于给定的接触者追踪策略，实现给定流行率或识别特定数量病例所需的筛查率是疾病流行率的递减函数。当流行率增加到阈值以上（并且停止接触者追踪）时，筛查率会不连续地跃升至更高水平。第三，当我们考虑不变或变化的流行率以及短期或长期成本时，这些定性结果仍然成立。
