Abstract
The causative agent of pertussis, Bordetella pertussis, has been known for more than 100 years. Vaccination against pertussis was included in the immunization schedules in most countries in the 1950s to result in a significant decrease in pertussis morbidity and mortality in children.
Nevertheless, pertussis still causes more than 249,000 deaths in children worldwide every year and is among the 10 leading causes of death in children. Since 1980, pertussis has been gradually re-emerging in most industrialized countries despite good vaccination coverage.
Increase in pertussis cases has been reported for all age groups. It documents that pertussis is not only a childhood disease but is prevalent also among adolescents and adults.
The morbidity and mortality of the smallest children are rising due to pertussis. The factors possibly involved in the higher incidence of pertussis include improved and more accurate reporting, higher quality diagnosis, decreased vaccination coverage, changes in vaccine quality, and the adaptation of B. pertussis to the vaccine resulting in waning immunity after vaccination and disease.
Therefore, a boost dose of the pertussis vaccine is given to adolescents and adults in a number of countries to prevent morbidity in these source groups.