Pertussis vaccine--an analysis of benefits, risks and costs.

Using decision analysis, we estimated the benefits, risks and costs of routine childhood immunization against pertussis. Without an immunization program, we predict that there would be a 71-fold increase in cases and an almost fourfold increase in deaths (2.0 to 7.6) per cohort of one million children. With a vaccination program, we predict 0.1 case of encephalitis associated with pertussis and five cases of post-vaccination encephalitis; without a program, there would be only 2.3 cases of encephalitis associated with pertussis. Community vaccination would reduce by 61 per cent the costs related to pertussis. Our analysis supports continuation of vaccination in routine childhood immunization programs, but suggests the need for more reliable data on complications from the vaccine, further study of the epidemiology of pertussis and development of a less toxic vaccine.