Committee efforts to develop a method of predicting likely lay and provider attitudes toward new vaccines were focused on two criteria. The technique had to allow conversion of attitudes into anticipated use rates by the target population, as well as permit ranking of vaccines relative to each other. The first requirement was imposed by the need for such an estimate in the calculation of relative benefits to be expected from the new vaccines.
The method proposed for predicting the likely acceptance of new vaccines is based conceptually on the health belief model. This approach structures the process of assessing attitudes in a fashion that, compared with other methods discussed below, more explicitly defines the factors considered and the judgments made on them. It also permits identification of the major determinants of behavior for each vaccine.
In some situations, attitudes toward new vaccines might be modified by educational programs designed to alter mistaken provider or lay perceptions. The committee decided, however, to adopt the assumption that no major educational campaigns would be initiated for these new products. This assumption was made solely to simplify the process of making predictions and should not be taken as an indication that such campaigns would not benefit public health. Moreover, the analytical model permits assessment of the likely effects of such campaigns on vaccine utilization, conditional on their success at altering the critical barriers.
Polling a relevant new vaccine target population and the providers who serve it probably would be the most accurate method of ascertaining likely attitudes. Although time and budgetary constraints precluded this option for the present study, the committee suggests that the National Institute of Allergy and infectious Diseases (NIAID), in collaboration with the Centers for Disease Control, consider methods for evaluating likely provider and lay attitudes based on polls in target populations.
If opinions are solicited from lay populations on likely vaccine acceptance, care should be taken to elicit information in a fashion comprehensible to responders, without informing them to an extent that would make them atypical of the group they are supposed to represent. For example, lay attitudes toward a vaccine for cytomegalovirus infection could be sought by describing it as a vaccine against a virus that is thought to be a major cause of congenital mental retardation.
To provide some indication of likely acceptance, the committee chose to act as surrogates for the various vaccine target populations and provider groups. Each candidate for accelerated development was scored twice—once from the assumed perspective of the appropriate lay group, and once from the assumed perspective of the appropriate provider group—on each of the four criteria shown to be of major importance in the health belief model: