title: Immunogenicity and safety of 13-valent pneumococcal conjugate vaccine in children previously immunized with 7-valent pneumococcal conjugate vaccine.
abstract: BACKGROUND
  The 7-valent pneumococcal conjugate vaccine (PCV7) has proven highly effective in preventing diseases caused by Streptococcus pneumoniae; however, in some regions, serotype coverage is limited. A recently licensed 13-valent PCV (PCV13) was developed to provide additional coverage globally. Children previously vaccinated with PCV7 could benefit from supplemental vaccination with PCV13 to provide protection against the 6 additional serotypes in PCV13. This open-label study evaluated the immunogenicity and safety of administering PCV13 to healthy children previously vaccinated with PCV7.
  
  
  METHODS
  Children between 15 months and 2 years of age (group 1) received 2 doses of PCV13; children between 2 and 5 years (group 2) received 1 dose. Antibodies (immunoglobulin G) against the polysaccharide antigens in PCV13 were measured before vaccination and 1 month after the final dose. Solicited local and systemic adverse events (AEs) were collected for 7 days postvaccination. Unsolicited and serious AEs were collected throughout.
  
  
  RESULTS
  A total of 284 subjects (group 1: n = 109; group 2: n = 175) had blood available for testing. Antipneumococcal immunoglobulin G geometric mean fold rises ranged from 2- to 19-fold for the PCV7 serotypes and from approximately 2- to 124-fold for the 6 additional serotypes. Additionally, postvaccination titers in excess of 0.35 μg/mL, the serologic correlate of immunity against pneumococcus for children, occurred in ≥98% of subjects in both groups for 12 of the 13 serotypes in PCV13. Slightly lower percentage of subjects, 94.5% and 92% of subjects in group 1 and group 2, respectively, had postvaccine titers for serotype 3 exceeding the serologic correlate of immunity. Reactogenicity was typically mild and self-limited, and unsolicited AEs reported were generally consistent with common childhood illnesses.
  
  
  CONCLUSIONS
  PCV13 was safe and immunogenic when administered to children who had previously received PCV7, and can be used for supplemental vaccination to provide additional protection against the 6 additional serotypes.
authors: Cincinnati Children's Hospital Medical Center, Department of Pediatrics, Cincinnati, OH 45229, USA. Robert.Frenck@cchmc.org
authors: Robert
authors: R
authors: Frenck
authors: Allison
authors: A
authors: Thompson
authors: Sylvia H
authors: SH
authors: Yeh
authors: Arnold
authors: A
authors: London
authors: Mohinder S
authors: MS
authors: Sidhu
authors: Scott
authors: S
authors: Patterson
authors: William C
authors: WC
authors: Gruber
authors: Emilio A
authors: EA
authors: Emini
authors: Daniel A
authors: DA
authors: Scott
authors: Alejandra
authors: A
authors: Gurtman
mesh_terms: D000914:Antibodies, Viral / Q000097:blood; D002675:Child, Preschool; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology*; D011446:Prospective Studies
chemical_list: C538862:13-valent pneumococcal vaccine; D000914:Antibodies, Viral; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D007074:Immunoglobulin G; D022242:Pneumococcal Vaccines