This paper considers an oligopolistic market for a vaccine, characterized by negative network effects, which stem from the free-riding behavior of individuals engaged in a vaccination game. Vaccine markets often suffer from three imperfections: high concentration, network effects, and a health externality (contagion). The first conclusion of the paper is that the negative network externality is important as a market distortion, as it may lead to significant welfare losses. The second and main part of the paper develops a two-part per-unit subsidy scheme that a social planner could use to target both consumers and producers of vaccines. The scope of such a subsidy scheme to induce the firms to produce the first-best output without network effects (which is the most ambitious first-best target) is investigated. In many cases, while the first-best is attainable, it requires negative prices for vaccines, which amounts to rewarding consumers to induce them to vaccinate.

中文翻译：

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具有健康和网络外部性的疫苗市场上最好的卫生政策

本文考虑了疫苗的寡头垄断市场，其特点是负面网络效应，这种效应源于参与疫苗接种游戏的个人的搭便车行为。疫苗市场常常存在三个缺陷：高度集中、网络效应和健康外部性（传染）。本文的第一个结论是，负网络外部性作为市场扭曲很重要，因为它可能导致重大的福利损失。本文的第二部分也是主要部分制定了一个由两部分组成的单位补贴计划，社会规划者可以利用该计划来针对疫苗的消费者和生产商。研究了这种补贴计划的范围，该计划旨在诱导企业在没有网络效应的情况下产生第一最佳产出（这是最雄心勃勃的第一最佳目标）。在许多情况下，虽然第一好的目标是可以实现的，但它需要疫苗的负价格，这相当于奖励消费者以诱导他们接种疫苗。