title: Group A Streptococcal Carriage and Seroepidemiology in Children up to 10 Years of Age in Australia.
abstract: BACKGROUND
  Group A streptococci (GAS) and other β-hemolytic streptococci (BHS) cause pharyngitis, severe invasive disease and serious nonsuppurative sequelae including rheumatic heart disease and post streptococcal glomerulonephritis. The aim of this study was to assess carriage rates and anti-streptococcal C5a peptidase (anti-SCP) IgG levels and identify epidemiologic factors related to carriage or seropositivity in Australian children.
  
  
  METHODS
  A throat swab and blood sample were collected for microbiological and serological analysis (anti-SCP IgG) in 542 healthy children aged 0-10 years. Sequence analysis of the SCP gene was performed. Serological analysis used a competitive Luminex Immunoassay designed to preferentially detect functional antibody.
  
  
  RESULTS
  GAS-positive culture prevalence in throat swabs was 5.0% (range 0-10%), with the highest rate in 5 and 9 years old children. The rate of non-GAS BHS carriage was low (<1%). The scp gene was present in all 22 isolates evaluated. As age of child increased, the rate of carriage increased; odds ratio, 1.14 (1.00, 1.29); P = 0.50. Geometric mean anti-SCP titers increased with each age-band from 2 to 7 years, then plateaued. Age, geographic location and number of children within the household were significantly associated with the presence of anti-SCP antibodies.
  
  
  CONCLUSIONS
  Children are exposed to GAS and other BHS at a young age, which is important for determining the target age for vaccination to protect before the period of risk.
authors.affiliation: From the *Vaccinology and Immunology Research Trials Unit, Women's and Children's Hospital, †School of Paediatrics and Reproductive Health, ‡Robinson Research Institute, University of Adelaide, North Adelaide, South Australia, Australia; §School of Paediatrics and Child Health, University of Western Australia, ¶Vaccine Trials Group, Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Subiaco, Western Australia, Australia; ‖Queensland Paediatric Infectious Diseases Laboratory, Queensland Children's Medical Research Institute, **Royal Children's Hospital, University of Queensland, Herston, Brisbane, Queensland, Australia; ††National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, The Children's Hospital at Westmead, Westmead, ‡‡Marie Bashir Institute, The University of Sydney, Sydney, New South Wales, Australia; §§Department of Paediatrics and Child Health, ANU Medical School, The Canberra Hospital, Canberra, Australian Capital Territory, Australia; and ¶¶Pfizer Vaccine Research, Pearl River, New York.
authors.forename: Helen S
authors.initials: HS
authors.lastname: Marshall
authors.forename: Peter
authors.initials: P
authors.lastname: Richmond
authors.forename: Michael
authors.initials: M
authors.lastname: Nissen
authors.forename: Stephen
authors.initials: S
authors.lastname: Lambert
authors.forename: Robert
authors.initials: R
authors.lastname: Booy
authors.forename: Graham
authors.initials: G
authors.lastname: Reynolds
authors.forename: Shite
authors.initials: S
authors.lastname: Sebastian
authors.forename: Michael
authors.initials: M
authors.lastname: Pride
authors.forename: Kathrin U
authors.initials: KU
authors.lastname: Jansen
authors.forename: Annaliesa S
authors.initials: AS
authors.lastname: Anderson
authors.forename: Ingrid L
authors.initials: IL
authors.lastname: Scully
mesh_terms: D018829:Adhesins, Bacterial / Q000276:immunology; D000907:Antibodies, Bacterial / Q000097:blood; D001315:Australia / Q000453:epidemiology; D002353:Carrier State / Q000453:epidemiology* / Q000276:immunology / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D010450:Endopeptidases / Q000276:immunology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D008297:Male; D010614:Pharynx / Q000382:microbiology*; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000276:immunology / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000276:immunology* / Q000302:isolation & purification
chemical_list: D018829:Adhesins, Bacterial; D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D010450:Endopeptidases; C053088:C5a peptidase