Pertussis and pertussis vaccine: further analysis of benefits, risks and costs.

Because of continuing debate about the benefits and risks of pertussis immunization, we recently published an analysis of benefits, risks, and costs based on an earlier study carried out in 1979. In the study, a hypothetical cohort of one million children was followed from birth to six years of age without and with a pertussis vaccination program. The study found a benefit: cost ratio of 11.1.: 1 associated with the pertussis vaccination program. Since publication of this study, questions have been raised regarding the result of the model if the observed U.S. age distribution of cases was used rather than the English distribution. In addition, there has recently been a substantial increase in the cost of pertussis vaccine. New data have also become available from the complete British National Childhood Encephalopathy Study. We have made further analyses of the model taking these factors into account. Even in the face of a 90-fold increase in vaccine costs and using "worst case" estimates of the risks of permanent damage associated with vaccine, our model continues to indicate that the benefits of pertussis vaccination outweigh the risks and the economic savings outweigh the costs.