Pertussis, caused by the strict human pathogen B. pertussis or Bordetella parapertussis, is a highly contagious, potentially life-threatening respiratory tract illness when it occurs in unprotected infants. Despite the introduction of acellular pertussis (aP) vaccines and great initial success of the immunization program, pertussis outbreaks were reported in adolescents and adults in Canada since 1993. This trend was demonstrated as shift in pertussis epidemiology from infants and young children. Further, pertussis in children associated with adolescents or adults cases have been reported in developed countries, in which siblings and adults were identified as the main source for the transmission of pertussis to young unvaccinated infants. This project emerged from a successful collaboration between Sanofi Pasteur and York University’s Institute for Health Research/Laboratory for Industrial and Applied Mathematics in developing and testing an age-structure and cost-effective economic models to understand the introduction of different aP vaccine (booster) recommendations (for <65 years old and >=65) on the transmission dynamics of B. pertussis, and cost-effectives in Canada.