传染控制的经济学

4.结论

　　通过政策对传染病做最优应对需要坚实的理论架构，以理解手段和目的，以及在私人部门与公共部门之间应该由谁来做哪些事情。流行病学与经济学的结合可以提供这样的理论基础。经济学进入这一合作领域时间不长，但可以带来重要帮助，而合作的首批成果就是提供深刻的认识。如果没有合适的理论架构，我们将不清楚应该从经验规律中总结些什么，以及如何把这些知识用于评估不同的传染控制策略。

　　目前，对于建模所需的各组成要件及其对政策定性分析的作用已取得了若干研究进展。不过模型是抽象的理念，针对特定疾病还需要做专门设定。只有结合特定传染病，我们才能枚举预防和治疗的具体方式，并弄清楚付出的努力同取得的成果之间的联系。迄今为止，经济学家针对特定传染病所做的大多数研究都是个人对艾滋病流行的某些行为反应，而且主要面向发达国家的同性恋群体（如Ahituv et al.，1996；Dow and Philipson，1996；Boozer and Philipson，2000；Bhattacharya et al.，2003；Auld，2006；Lakdawalla et al.,2006；Francis,2008）。经济学家还针对其他传染病开展了若干研究，包括恰加斯氏病（CastilloRiqueline et al.,2008）、肠内寄生虫病（Miguel and Kremer,2004）、疟疾（Cohen and Dupas,2010）与血吸虫病（Wiemer,1987）等。这些研究都没有充分采用本文介绍的动态外部性研究方法（Gersovitz and Hammer,2004），因此无法得出与政府干预有关的最终结论。

　　（余江 译）

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