If infectious people can infect other people, who in turn can infect others, and so on--the pure infection externality--government subsidies to affect private behavior should equally favor preventive and curative activities, if people recover to become susceptible again. Otherwise, other subsidy...

Economics plus epidemiology provide models of infections and associated behavior of private individuals. They show how infections generate problems of dynamic externalities, scope for government to offset externalities, and problems of the second best when government cannot or does not. Features...