The health belief model parameters (perceptions of risk of illness, severity, vaccination benefits, and barriers) used to predict vaccine utilization are described in Chapter 6, where scores assigned to various vaccines are displayed together for comparison.

Lay perception of the risk of illness from parainfluenza viruses is thought to be low, but the more recognized forms of illness, such as pneumonia, are thought to be perceived as relatively serious. The general belief by parents in pediatric vaccination would result in a moderately high lay score for benefits, while the cost and possible confusion over problems associated with the influenza vaccine probably would present moderate barriers to acceptance.

Provider recognition of the moderate risk of parainfluenza viral illness probably would be reasonably accurate. The perception of the seriousness of the more severe forms of the disease also would be accurate. Physician rating of the benefits of vaccination would be moderate because of the limits on protection against illness. The barriers, while low, might be affected by association with problems related to previous vaccine candidates that involved fusion proteins, such as the RSV vaccine.

The scope and purpose of the calculations included below are described in Chapters 4 and 7. These calculations are based on certain simplifying procedures and assumptions that have been judged not to compromise their utility for this study. The total costs should be taken only as an approximation of the direct cost of this disease.