new pertussis vaccine over a prolonged period. On the other hand, Robbins (1984) has argued that extensive field trials to study the efficacy of a new pertussis vaccine may not be necessary if the proposed vaccine passes the appropriate potency and toxicity requirements; can be characterized fully in biochemical, biophysical, and immunologic terms; and can be shown to meet a series of additional biochemical standards. Such an approach presumes that quantitative serologic assays for antibodies to pertussis components could be established and standardized, and that a relationship between antibody response and the existing potency standards could be established.
It must be recognized that should an improved, less reactogenic vaccine become available, it will be exceptionally difficult to define the frequency (if any) of rare but potentially catastrophic reactions without administration of the vaccine to millions of children. The difficulties involved in differentiating vaccine-caused neurological problems from similar events that occur naturally in some children in the first six months of life will continue to exist.
The health belief model parameters (perceptions of risk of illness, severity, vaccination benefits, and barriers) used in predicting vaccine utilization are described in Chapter 6, where scores assigned to various vaccines are displayed together to facilitate comparison.
Lay persons undoubtedly perceive the risk of pertussis as very low, although they continue to believe that the disease is serious if it occurs. Most individuals assume that the vaccine is effective.
Concern about adverse reactions has been a significant barrier in countries other than the U.S. during recent years. The vaccine’s safety has been debated widely in both medical and lay publications. An example of this phenomenon occurred in the U.S. in April 1982: a single television program aired on the East Coast resulted in a transient decline in pertussis vaccine usage in the viewing area.
Nevertheless, usage of the DPT vaccine in the U.S. remains high, supported by strong recommendations from the American Academy of Pediatrics and the CDC’s Advisory Committee on Immunization Practices. Inclusion of the improved acellular pertussis component in the vaccine will strengthen this acceptance. Existing school-entry immunization laws will ensure a high level of utilization.
Provider perceptions of the risk of pertussis may be slightly higher than that of the lay community, but other scores on health belief model parameters will be similar.