title: Parapertussis and pertussis: differences and similarities in incidence, clinical course, and antibody responses.
abstract: OBJECTIVE
  To compare the incidence, clinical course, and serologic response to Bordetella antigens in patients with parapertussis and pertussis.
  
  
  METHODS
  Two studies were performed in Sweden during the 1990s, when pertussis vaccines were used only in clinical trials. Study I was a retrospective study of patients with positive Bordetella cultures obtained in clinical routine, and study II involved an active search for patients with Bordetella infections during a placebo-controlled trial of a pertussis toxoid vaccine.
  
  
  RESULTS
  Study I includes 58, and study II 23 patients with parapertussis. In study I, the incidence of parapertussis was 0.016 cases per 100 person years in children 0 to 6 years old and 0 in older children and adults. In study II, the incidence rates of parapertussis and pertussis were 0.2 and 16.2 per 100 person years, respectively, in children followed from 3 months to 3 years of age. The median number of days with cough was 21 in parapertussis and 59 in pertussis. The proportions of children with whooping and vomiting were lower in parapertussis than in pertussis. Geometric mean serum filamentous hemagglutinin IgG increased from 6 to 63, and pertactin IgG from 4 to 12 units/mL in parapertussis patients, which was similar to increases in children with pertussis.
  
  
  CONCLUSIONS
  Disease caused by Bordetella parapertussis is diagnosed less commonly and is milder and of shorter duration than disease caused by Bordetella pertussis. Parapertussis induced serum IgG against filamentous hemagglutinin and pertactin of similar magnitude as does pertussis, and did not induce serum IgG against pertussis toxin.
authors.affiliation: The Göteborg Pertussis Vaccine Trial, the Göteborg Primary Health Care System, Göteborg, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Bergfors
authors.forename: B
authors.initials: B
authors.lastname: Trollfors
authors.forename: J
authors.initials: J
authors.lastname: Taranger
authors.forename: T
authors.initials: T
authors.lastname: Lagergård
authors.forename: V
authors.initials: V
authors.lastname: Sundh
authors.forename: G
authors.initials: G
authors.lastname: Zackrisson
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology; D001884:Bordetella / Q000145:classification / Q000276:immunology*; D001885:Bordetella Infections / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control; D001886:Bordetella pertussis / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D015994:Incidence; D007223:Infant; D008297:Male; D037342:Pertussis Toxin; D010567:Pertussis Vaccine / Q000276:immunology*; D012189:Retrospective Studies; D010566:Virulence Factors, Bordetella / Q000276:immunology; D014917:Whooping Cough / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control
chemical_list: D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D007074:Immunoglobulin G; D010567:Pertussis Vaccine; D010566:Virulence Factors, Bordetella; C068929:pertactin; D037342:Pertussis Toxin