Pertussis immunization in the global pertussis initiative European region: recommended strategies and implementation considerations.

Approaches to pertussis diagnosis, surveillance and immunization vary widely across Europe. Nonetheless most countries report high levels of vaccine coverage in infants and toddlers, and significant reductions in infant morbidity and mortality have been achieved. As a consequence of the effective protection of infants and toddlers, the absolute incidence of pertussis has substantially decreased, but the relative proportion of older age groups, adolescents and adults in particular, has increased. These groups, however, are a relevant source of infection of unimmunized or incompletely immunized infants. In addition to efficient childhood vaccination, other approaches to pertussis immunization are required. Among the various strategies evaluated, 3 were recommended by the European participants in the Global Pertussis Initiative that might be adapted to each country's specific needs: the reinforcement of implementation of current schedules, the addition of an extra dose of vaccine to current immunization schedules and the selective immunization of health care workers, which is already included in a European Commission directive. The main barriers to the acceptance of these strategies are low awareness of pertussis in immunized populations, poor recognition of the disease in adults and adolescents, lack of standardized diagnostic criteria and poor access to laboratory confirmation of the diagnosis. These obstacles have led to underreporting of pertussis and an underestimation of the disease burden. Actions to overcome these issues are crucial to the implementation of new or improved immunization strategies to combat pertussis in Europe.