title: The 23-valent pneumococcal polysaccharide vaccine does not provide additional serotype antibody protection in children who have been primed with two doses of heptavalent pneumococcal conjugate vaccine.
abstract: Current guidelines recommend up to two doses of the pneumococcal conjugate heptavalent vaccine (PCV-7) in children up to 5 years old followed by and a dose of the polysaccharide vaccine (PPV-23) for patients over 2 years old to broaden serotype immunity. We assessed the serotype responses to two doses of PCV-7 and a dose of PPV-23 in a cohort of children in the 2-16-year age range in order to determine whether PPV-23 induced effective immunity to non-PCV-7 serotypes. Pneumococcal antibody concentrations to the seven serotypes covered by PCV-7 and five additional serotypes covered by PPV-23 but not PCV-7 were measured in 60 children aged 2-16 years. None of the children had a primary antibody immunodeficiency. Vaccinated children had 7-30-fold higher antibody concentrations than unvaccinated children to all serotypes contained in the PCV-7 (P<0.001). In contrast, serotypes covered by the PPV-23 but not PCV-7 were only one- to two-fold higher and there was no significant increase in the number of children who had protective concentrations of antibody (> or =0.35 mcg/ml) against these serotypes. In this cohort of children, PPV-23 vaccine did not broaden the protection in vitro against potentially pathogenic strains of Streptococcus pneumoniae. We call into question the recommendation to use the PPV-23 in children.
authors.affiliation: Health Protection Agency, Clinical Sciences Building II, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL, United Kingdom.
authors.forename: Paul
authors.initials: P
authors.lastname: Balmer
authors.forename: Ray
authors.initials: R
authors.lastname: Borrow
authors.forename: Peter D
authors.initials: PD
authors.lastname: Arkwright
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000907:Antibodies, Bacterial / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D022401:Meningococcal Vaccines / Q000276:immunology*; D022242:Pneumococcal Vaccines / Q000276:immunology*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000276:immunology*; D014611:Vaccination
chemical_list: C414006:23-valent pneumococcal capsular polysaccharide vaccine; D000907:Antibodies, Bacterial; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D007074:Immunoglobulin G; D022401:Meningococcal Vaccines; D022242:Pneumococcal Vaccines