title: Immunogenicity and safety of the eleven valent pneumococcal polysaccharide-protein D conjugate vaccine in infants.
abstract: BACKGROUND
  Development is ongoing to increase the serotype coverage of pneumococcal conjugate vaccines. We report here the immunogenicity and safety of a new 11-valent pneumococcal conjugate vaccine (Pn-PD) in infants.
  
  
  METHODS
  In a randomized, single blind study, 154 Finnish infants received 1 of 3 regimens: 4 doses of Pn-PD at 2, 4, 6 and 12-15 months; 3 doses of the Pn-PD at 2, 4 and 6 months and 1 dose of 23-valent polysaccharide vaccine (PncPS) at 12-15 months; or 3 doses of the hepatitis B vaccine at 2, 4 and 6 months and Pn-PD at 12-15 months. Serum IgG antibodies to vaccine serotypes 1, 3, 4, 5, 6B, 7F, 9V, 14, 18C, 19F and 23F were measured with an enzyme immunoassay at the ages of 2, 7 and 12-15 months and at 4 or 28 days after the last vaccination. Local and systemic reactions were recorded by parents during 8 days after each dose. Serious adverse reactions were recorded during the entire study period.
  
  
  RESULTS
  There was a significant increase in the IgG concentrations to vaccine serotypes after 3 doses of Pn-PD. Antibody concentrations after the primary series varied between 1.26 and 4.92 microg/ml depending on the serotype and study group. PncPS vaccine induced a better booster response than the Pn-PD, measured at 28 days after the fourth dose. IgG concentrations after the Pn-PD booster ranged between 1.60 and 9.63 microg/ml and after the PncPS booster between 4.24 and 40.54 microg/ml, depending on the serotype. The antibody concentrations after the first dose of Pn-PD administered at 12-15 months increased significantly but were lower than after the fourth dose at the same age. No significant antibody increase was measured 4 days after the vaccinations at 12-15 months. The safety profile of the vaccine was acceptable.
  
  
  CONCLUSIONS
  The Pn-PD we tested was immunogenic and safe in infants.
authors.affiliation: National Public Health Institute, Helsinki, Finland.
authors.forename: Anu
authors.initials: A
authors.lastname: Nurkka
authors.forename: Jaana
authors.initials: J
authors.lastname: Joensuu
authors.forename: Isabelle
authors.initials: I
authors.lastname: Henckaerts
authors.forename: Pascal
authors.initials: P
authors.lastname: Peeters
authors.forename: Jan
authors.initials: J
authors.lastname: Poolman
authors.forename: Terhi
authors.initials: T
authors.lastname: Kilpi
authors.forename: Helena
authors.initials: H
authors.lastname: Käyhty
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology*; D005260:Female; D005387:Finland; D005500:Follow-Up Studies; D006801:Humans; D007109:Immunity / Q000502:physiology; D007115:Immunization Schedule; D007223:Infant; D008297:Male; D011008:Pneumococcal Infections / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D012449:Safety; D016037:Single-Blind Method; D014611:Vaccination / Q000379:methods; D018074:Vaccines, Conjugate / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate