The University of Sydney, New South Wales, Australia.
Vaccine effectiveness in the first large-scale use of adolescent pertussis vaccine in Australia was evaluated by the screening method. Vaccine effectiveness was 78.0% (95% CI: 60.7-87.6%) for all study cases (n = 167), increasing to 85.4% (95% CI: 83.0-87.5%) for laboratory-confirmed cases (n = 155). Effectiveness should be comparable in settings with similar programs, such as the United States and Canada.