title: Long-term impact of pneumococcal polysaccharide vaccination on nasopharyngeal carriage in children previously vaccinated with various pneumococcal conjugate vaccine regimes.
abstract: Previously, the Fiji Pneumococcal Project (FiPP) evaluated reduced dose immunization schedules that incorporated pneumococcal protein conjugate and/or polysaccharide vaccine (PCV7 and 23vPPV, respectively). Immune hyporesponsiveness was observed in children vaccinated with 23vPPV at 12 months of age compared with children who did not receive 23vPPV. Here we assess the long-term impact of 23vPPV vaccination on nasopharyngeal carriage rates and densities of Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus and Moraxella catarrhalis. Nasopharyngeal swabs (n=194) were obtained from healthy children who participated in FiPP (now aged 5-7 years). S. pneumoniae were isolated and identified by standard culture-based methods, and serotyped using latex agglutination and the Quellung reaction. Carriage rates and densities of S. pneumoniae, H. influenzae, S. aureus and M. catarrhalis were determined using real-time quantitative PCR. There were no differences in the rate or density of S. pneumoniae, H. influenzae or M. catarrhalis carriage by PCV7 dose or 23vPPV vaccination in the vaccinated participants overall. However, differences were observed between the two main ethnic groups: Fijian children of Indian descent (Indo-Fijian) were less likely to carry S. pneumoniae, H. influenzae and M. catarrhalis, and there was evidence of a higher carriage rate of S. aureus compared with indigenous Fijian (iTaukei) children. Polysaccharide vaccination appeared to have effects that varied between ethnic groups, with 23vPPV vaccination associated with a higher carriage rate of S. aureus in iTaukei children, while there was a lower carriage rate of S. pneumoniae associated with 23vPPV vaccination in Indo-Fijian children. Overall, polysaccharide vaccination had no long-term impact on pneumococcal carriage, but may have impacted on S. aureus carriage and have varying effects in ethnic groups, suggesting current WHO vaccine schedule recommendations against the use of 23vPPV in children under two years of age are appropriate.
authors.affiliation: Pneumococcal Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC, Australia; Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia.
authors.forename: Laura K
authors.initials: LK
authors.lastname: Boelsen
authors.affiliation: Pneumococcal Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC, Australia.
authors.forename: Eileen M
authors.initials: EM
authors.lastname: Dunne
authors.affiliation: Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia; Menzies School of Health Research, Darwin, NT, Australia.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Lamb
authors.affiliation: Clinical Epidemiology & Biostatistics Unit, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC, Australia.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Bright
authors.affiliation: Center for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore, Singapore; Department of International Health, University of Tampere, Tampere, Finland.
authors.forename: Yin Bun
authors.initials: YB
authors.lastname: Cheung
authors.affiliation: Ministry of Health, Suva, Fiji.
authors.forename: Lisi
authors.initials: L
authors.lastname: Tikoduadua
authors.affiliation: Pneumococcal Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC, Australia; Centre for International Child Health, Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia.
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Russell
authors.affiliation: Pneumococcal Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC, Australia; London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: E Kim
authors.initials: EK
authors.lastname: Mulholland
authors.affiliation: Pneumococcal Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC, Australia; Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia; Allergy and Immune Disorders, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC, Australia.
authors.forename: Paul V
authors.initials: PV
authors.lastname: Licciardi
authors.affiliation: Pneumococcal Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC, Australia; Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia; Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, VIC, Australia. Electronic address: catherine.satzke@mcri.edu.au.
authors.forename: Catherine
authors.initials: C
authors.lastname: Satzke
mesh_terms: D002353:Carrier State / Q000208:ethnology* / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D005367:Fiji; D006193:Haemophilus influenzae / Q000302:isolation & purification; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D001936:Moraxella catarrhalis / Q000302:isolation & purification; D009305:Nasopharynx / Q000382:microbiology*; D022242:Pneumococcal Vaccines / Q000627:therapeutic use*; D065288:Serogroup; D013211:Staphylococcus aureus / Q000302:isolation & purification; D013296:Streptococcus pneumoniae / Q000145:classification / Q000302:isolation & purification
chemical_list: C414006:23-valent pneumococcal capsular polysaccharide vaccine; D022242:Pneumococcal Vaccines
keywords: Ethnicity; Nasopharyngeal carriage; Pneumococcal conjugate vaccine; Pneumococcal polysaccharide vaccine; Staphylococcus aureus; Streptococcus pneumoniae