title: Immunogenicity and tolerability of a heptavalent pneumococcal conjugate vaccine administered at 3, 5 and 12 months of age.
abstract: BACKGROUND
  The recommended vaccination schedule for the pneumococcal conjugate vaccine (PCV) includes 4 immunizations, according to the national programs in the United States and some European countries. Other countries use a national schedule for routine vaccinations in early childhood that includes only 3 doses.
  
  
  OBJECTIVE
  The goals were to assess the immunogenicity and tolerability of PCV with a vaccination schedule that included 3 doses during the first 1 year of life (a 2+1 dose schedule) and to determine the immune responses to concomitantly administered Haemophilus influenzae type b (Hib) vaccine.
  
  
  METHODS
  A total of 101 healthy Swedish infants were enrolled in an open, nonrandomized, multicenter study. PCV was administered concomitantly with (at separate sites) a diphtheria-tetanus toxoids-acellular pertussis vaccine, inactivated polio vaccine and Hib conjugate vaccine combination at 3, 5 and 12 months of age. IgG antibody concentrations for the 7 serotypes included in the PCV and the Hib capsular polysaccharide in serum samples taken at 3, 6, 12 and 13 months were determined with enzyme immunoassays. Local and systemic reactions were monitored for 3 days after each immunization, and serious adverse reactions were monitored for the whole study period.
  
  
  RESULTS
  Two doses of PCV induced satisfactory antibody responses, with the exception of serotypes 6B and 23F. The third dose evoked strong responses for all serotypes, which suggests good immunologic priming with the primary series of 2 doses. The mean anti-Hib antibody concentrations were similar to those noted in earlier studies among Swedish children. The PCV was well tolerated.
  
  
  CONCLUSIONS
  The pneumococcal antibody concentrations at 13 months were comparable with those noted previously with the 4-dose schedule. The results suggest that the implementation of a 2+1 dose schedule for PCV should be considered.
authors.affiliation: Department of Vaccines, National Public Health Institute, Helsinki, Finland.
authors.forename: Helena
authors.initials: H
authors.lastname: Käyhty
authors.forename: Heidi
authors.initials: H
authors.lastname: Ahman
authors.forename: Karin
authors.initials: K
authors.lastname: Eriksson
authors.forename: Mikael
authors.initials: M
authors.lastname: Sörberg
authors.forename: Lennart
authors.initials: L
authors.lastname: Nilsson
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood; D018073:Haemophilus Vaccines / Q000276:immunology; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D022401:Meningococcal Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D022242:Pneumococcal Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D013296:Streptococcus pneumoniae / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D018073:Haemophilus Vaccines; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022401:Meningococcal Vaccines; D022242:Pneumococcal Vaccines