Adolescent and adult pertussis vaccination: computer simulations of five new strategies

Approximately one million adult pertussis cases occur annually in the US, and infants still die from pertussis. Computer simulations were used to predict the impact of vaccination of children, adults and/or adolescents, and household members of newborns (cocoon strategy). Childhood vaccination greatly reduced cases in children, but increased the incidence in adolescents and adults. Routine adolescent and adult vaccination had a large direct effect, whereas the cocoon strategy had a predominantly indirect effect on young infants. The number needed to vaccinate (NNV) to prevent a case of typical pertussis in the entire population was lowest for the adolescent strategy. The cocoon strategy had the lowest NNV to prevent a case of typical pertussis in young infants. The current vaccination schedule, local epidemiological data, age-specific cost of pertussis cases, and accessibility of the target population will determine which strategy has the highest likelihood of success in achieving the public health goal. (C) 2004 Elsevier Ltd. All rights reserved.