Lessons from a mature acellular pertussis vaccination program and strategies to overcome suboptimal vaccine effectiveness.

Despite high vaccination coverage among children and adolescents, pertussis remains a public health problem, with large outbreaks occurring periodically in the US and other developed countries. We examine lessons learned more than 20 years after implementation of programs which use only acellular pertussis vaccines and propose avenues for possible effective use of acellular pertussis vaccine to prevent large outbreaks. Acellular pertussis vaccines were introduced more than 20 years ago, yet the incidence of pertussis has been increasing over the past decade, with periodic large outbreaks marked by notable shifts in disease burden from infants and young children toward fully vaccinated adolescents and young adults. This age shift is mainly driven by the waning of vaccine immunity. To better protect adolescents against pertussis, modification of the current acellular pertussis vaccination schedule or adoption of new vaccination strategies should be considered. For infants not yet eligible to be vaccinated, maternal vaccination against pertussis during pregnancy is an effective way to protect infants from infection, severe disease and death. Implementation of maternal vaccination programs should be encouraged in countries without one or efforts to improve coverage should be supported in countries with existing program.