title: 13-Valent pneumococcal conjugate vaccine (PCV13) in children partially immunized with 7-valent pneumococcal conjugate vaccine (PCV7): a phase 3, open-label trial.
abstract: BACKGROUND
  As 13-valent pneumococcal conjugate vaccine (PCV13) is introduced, children who began vaccination with 7-valent pneumococcal conjugate vaccine (PCV7) may complete their vaccination with PCV13. This open-label phase 3 study evaluated immunogenicity and safety of PCV13 in Swedish infants and toddlers previously given 1 or 2 doses of PCV7 during infancy.
  
  
  METHODS
  Healthy infants previously given PCV7 at ages 3 months (group 1; n=118) or 3 and 5 months (group 2; n=116) received PCV13 at ages 5 (group 1) and 12 months (both groups). IgG responses were assessed 1 month after each PCV13 dose and before the 12-month dose. Local reactions and systemic events were collected for 7 days postvaccination. Other adverse events were also collected.
  
  
  RESULTS
  Post-5-month dose, IgG geometric mean concentrations (GMCs) in group 1 were 1.56-4.70 μg/ml for most PCV7 serotypes except 6B (0.40 μg/ml) and 23F (0.57 μg/ml) and 0.72-1.88 μg/ml for most of the 6 additional serotypes, except 6A (0.28 μg/ml). Post-12-month dose, IgG GMCs for the PCV7 serotypes were 2.93-9.63 μg/ml (group 1) and 3.33-9.30 μg/ml (group 2); and for the 6 additional serotypes, 1.85-14.65 μg/ml (group 1) and 1.34-13.16 μg/ml (group 2). GMCs increased by >4-fold in both groups from pre- to post-12-month dose. Proportions of subjects in group 1 with pneumococcal serotype-specific IgG concentrations ≥0.35 μg/ml (WHO-designated postprimary reference antibody level) post-5-month dose were 92.2-99.1% for most PCV7 serotypes except 6B (53.0%) and 23F (62.6%) and 80.9-100.0% for most of the 6 additional serotypes except 6A (36.8%). Local reactions and fever were mostly mild or moderate.
  
  
  CONCLUSIONS
  PCV13 was immunogenic and safe in infants and toddlers previously partially immunized with PCV7. Even a single dose in an infant or toddler induces an immune response to the 6 additional serotypes.
authors.affiliation: Department of Clinical Sciences, Pediatrics, Umeå University, Umeå, Sweden. sven.arne.silfverdal@pediatri.umu.se
authors.forename: Sven Arne
authors.initials: SA
authors.lastname: Silfverdal
authors.forename: Carl-Erik
authors.initials: CE
authors.lastname: Flodmark
authors.forename: Lars
authors.initials: L
authors.lastname: Rombo
authors.forename: Susan P
authors.initials: SP
authors.lastname: Tansey
authors.forename: Mohinder
authors.initials: M
authors.lastname: Sidhu
authors.forename: James
authors.initials: J
authors.lastname: Trammel
authors.forename: Emilio A
authors.initials: EA
authors.lastname: Emini
authors.forename: William C
authors.initials: WC
authors.lastname: Gruber
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Scott
authors.forename: Alejandra
authors.initials: A
authors.lastname: Gurtman
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology / Q000473:pathology; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D011008:Pneumococcal Infections / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology*; D013548:Sweden
chemical_list: C538862:13-valent pneumococcal vaccine; D000907:Antibodies, Bacterial; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D007074:Immunoglobulin G; D022242:Pneumococcal Vaccines