The swine-influenza decision.

We analyzed the economic aspects of mass immunization against swine-like influenza in 1976-1977, and have used the Delphi technic for estimating the likelihood and characteristics of an epidemic. If an epidemic occurs and no preventive efforts are made, total costs could exceed $6 billion for the whole population and $3 billion for those in the high-risk group. Expected net benefits from immunization vary with (1) the target population, (2) costs of vaccine administration and (3) vaccine acceptance rates. With an epidemic probability of 0.10 and with costs of purchasing and administering the vaccine each estimated at $0.50 per person in the target population, maximum net benefits cannot be obtained by an offer of vaccine to the entire population. Economic considerations do not require limitation of vaccination to high-risk groups. If the program is restricted to adults 25 years of age and over, and if acceptance rates exceed 59 per cent, the program is economically justifiable.