title: National pertussis surveillance in South Korea 1955-2011: epidemiological and clinical trends.
abstract: BACKGROUND
  Although there has been substantial progress in controlling pertussis in South Korea, the reported number of pertussis case-patients has gradually been increasing during the last decade. To address this, we summarized the surveillance data on pertussis collected during the period 1955-2011. Detailed epidemiologic and clinical data were determined, primarily using data from recent years.
  
  
  METHODS
  We analyzed data from the national surveillance system to describe the occurrence of pertussis. The annual numbers of reported pertussis case-patients were identified for the period 1955-2000. For 2001-2009, information including limited demographic characteristics and the date of onset of symptoms were identified. For 2010-2011, detailed epidemiologic and clinical information of reported pertussis case-patients were collected.
  
  
  RESULTS
  During 1955-2011, the secular trend was characterized by a gradual decrease in the reported number of cases from 1955 to the late 1990s, then a recent increase starting in the early 2000s. In 2009, a large number of reported cases occurred in infants <1 year of age. In 2011, an increase in reported cases among adolescents and adults aged ≥15 years was observed. During 2010-2011, 29.8% of reported cases were not immunized and 11.3% had not been immunized in a timely manner. Of adolescents and adults aged ≥15 years, 91.7% did not have a record of immunization.
  
  
  CONCLUSIONS
  During 2010-2011, a shift in age group was observed in pertussis case-patients: 33.8% were young infants <3 months of age and 29.0% were adolescents and adults ≥15 years of age. Considering that infants without timely vaccination may be vulnerable to an increased risk of pertussis infection, steps to provide timely vaccination to infants, to provide Tdap vaccination to adolescents and adults, and to enhance surveillance to capture adult pertussis cases should be taken in South Korea.
authors.affiliation: Division of Vaccine Preventable Disease Control and National Immunization Program, Korea Centers for Disease Control and Prevention, Osong, Korea.
authors.forename: Young June
authors.initials: YJ
authors.lastname: Choe
authors.forename: Young-Joon
authors.initials: YJ
authors.lastname: Park
authors.forename: Chaewon
authors.initials: C
authors.lastname: Jung
authors.forename: Geun-Ryang
authors.initials: GR
authors.lastname: Bae
authors.forename: Duk-hyoung
authors.initials: DH
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D001886:Bordetella pertussis / Q000302:isolation & purification*; D062665:Epidemiological Monitoring; D005260:Female; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D008297:Male; D010567:Pertussis Vaccine / Q000008:administration & dosage*; D056910:Republic of Korea / Q000453:epidemiology; D014611:Vaccination / Q000379:methods; D014917:Whooping Cough / Q000453:epidemiology* / Q000517:prevention & control; D055815:Young Adult
chemical_list: D010567:Pertussis Vaccine