RESUMO
OBJECTIVE: Pertussis is a highly contagious infection affecting mainly children. Acellular pertussis vaccines were recently introduced in Canada based on evidence of improved safety and efficacy over whole cell vaccines, the current standard of care. The following study reports the economic impact of replacing the whole cell vaccine (wP) by a new acellular vaccine (aP) in the Ontario pertussis immunisation programme. DESIGN: For a hypothetical cohort of 100,000 children from birth to the age of 8 years, the costs and consequences of pertussis vaccination with either aP or wP were compared. A decision analytical model was constructed for vaccine delivery, treatment of pertussis cases and vaccine adverse events, with analyses from the viewpoints of the Ontario Ministry of Health and society. MAIN OUTCOME MEASURES AND RESULTS: The main outcomes were expected number of pertussis cases, hospitalisations, and workdays lost by parents. Data on vaccine effectiveness, pertussis incidence, and other parameters used in the model were from published literature. Costs were discounted at 5%, and extensive sensitivity analyses were undertaken. Over 8 years, in a cohort of 100,000 children, the introduction of aP would prevent 10,500 cases of pertussis, avoiding 504 hospital admissions and 73,500 days of work absence. For Ontario, healthcare cost savings over the same period would amount to 275,585 Canadian dollars ($Can), and societal savings to $Can9,752,864