Does society benefit from private measures to mitigate infectious disease risks? Since mitigation reduces both peak prevalence and the number of people who fall ill, the answer might appear to be yes. But mitigation also prolongs epidemics and therefore the time susceptible people engage in activities to avoid infection. These avoidance activities come at a cost—in lost production or consumption, for example. Whether private mitigation yields net social benefits depends on the social weight given to the costs of illness and illness avoidance, now and into the future. We show that, for a large class of infectious diseases, private risk mitigation is socially beneficial. However, in cases where society discounts the future at either very low or very high rates relative to private individuals, or where it places a low weight on the private cost of illness, the social cost of illness under proportionate mixing (doing nothing) may be lower than the social cost of illness under preferential mixing (avoiding infectious individuals). That is, under some circumstances, society would prefer shorter, more intense epidemics without avoidance costs over longer, less intense epidemics with avoidance costs. A sobering (although not surprising) implication of this is that poorer societies should be expected to promote less private disease-risk mitigation than richer societies.

中文翻译：

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减轻私人传染病风险的社会效益。

社会是否从减轻传染病风险的私人措施中受益？由于缓解措施既可以减少高峰期患病率，也可以减少生病的人数，所以答案似乎是肯定的。但是缓解措施还延长了流行病的时间，因此易受感染时间的人们从事避免感染的活动。这些回避活动是以一定的代价为代价的，例如，损失了生产或消耗。私人缓解是否会产生净社会效益，取决于现在和将来对疾病和避免疾病费用的社会影响力。我们表明，对于一大类传染病，减轻私人风险对社会有益。但是，如果社会相对于私人以非常低或非常高的价格折现未来，或在不重视私人疾病成本的情况下，按比例混合（不采取任何措施）下疾病的社会成本可能低于在优先混合下（避免感染个人）的疾病社会成本。就是说，在某些情况下，社会宁愿较短的，强度更大的流行病而没有避免费用，而不是较长，强度较小的流行病而又具有避免费用。一个令人发人深省的（尽管并不令人惊讶）的含义是，与较富裕的社会相比，较贫穷的社会应能减少对私人疾病风险的缓解。在没有回避成本的情况下发生更严重的流行病，而在避免回避成本的情况下发生的时间越长，强度越低的流行病。一个令人发人深省的（尽管并不令人惊讶）的含义是，与较富裕的社会相比，较贫穷的社会应能减少对私人疾病风险的缓解。在没有回避成本的情况下发生更严重的流行病，而在避免回避成本的情况下发生的时间越长，强度越低的流行病。一个令人发人深省的（尽管并不令人惊讶）的含义是，与较富裕的社会相比，较贫穷的社会应能减少对私人疾病风险的缓解。