title: Outcomes of Bordetella pertussis infection in different age groups of an immunized population.
abstract: Outcomes of Bordetella pertussis infection were studied in 3 age groups (1-3, 4-6, and 7-15 years) during outbreaks in one day care center (n = 29) and in two elementary schools (n = 210). A total of 76 children were confirmed as having B. pertussis infection; 74 were confirmed by polymerase chain reaction (PCR) and 18 by culture. A positive PCR result was less common in children 1-3 years old than in those 4-6 (P = .006). Asymptomatic B. pertussis infection was more common in preschool children than in schoolchildren (P < .001), whereas schoolchildren presented with symptoms compatible with clinical pertussis more often than preschool children (60/210 vs. 3/29, P = .029). In the community of 12,691, the attack rate (laboratory-confirmed patients/100,000) was 317 in children < 4 years, 1838 in children 4-6 years, 2535 in children 7-15 years, and 248 in persons > 15 years. The protection provided by conventional pertussis vaccine is evidently rather short-lived, and booster vaccinations are needed to eradicate pertussis among schoolchildren and adults.
authors.affiliation: National Public Health Institute, Department in Turku, Finland.
authors.forename: Q
authors.initials: Q
authors.lastname: He
authors.forename: M K
authors.initials: MK
authors.lastname: Viljanen
authors.forename: S
authors.initials: S
authors.lastname: Nikkari
authors.forename: R
authors.initials: R
authors.lastname: Lyytikäinen
authors.forename: J
authors.initials: J
authors.lastname: Mertsola
mesh_terms: D000367:Age Factors; D000907:Antibodies, Bacterial / Q000097:blood; D001886:Bordetella pertussis / Q000302:isolation & purification; D002648:Child; D002675:Child, Preschool; D005260:Female; D005387:Finland; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007223:Infant; D008297:Male; D010567:Pertussis Vaccine; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D016896:Treatment Outcome; D014917:Whooping Cough / Q000276:immunology / Q000628:therapy*
chemical_list: D000907:Antibodies, Bacterial; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D010567:Pertussis Vaccine