title: Invasive pneumococcal diseases in birth cohorts vaccinated with PCV-7 and/or PHiD-CV in the province of Quebec, Canada.
abstract: BACKGROUND
  The 10-valent protein D pneumococcal conjugate vaccine (PHiD-CV) was licensed on the basis of immunogenicity studies and there are no published data on its effectiveness to prevent invasive pneumococcal disease (IPD). In the province of Quebec, Canada, PHiD-CV was introduced in the summer of 2009, replacing the 7-valent CRM197 vaccine (PCV-7). Transition to the new vaccine was recommended regardless of the number of PCV7 doses already administered.
  
  
  METHODS
  IPD rates in children born in 2007-2010 and observed up to the end of 2010 were computed from laboratory surveillance data. The main vaccine used for the infant primary immunization series (mainly 2 doses at 2-4 months) and the toddler (12 months) booster dose was inferred from the Quebec City Immunization Registry data.
  
  
  RESULTS
  IPD rates were significantly lower in the cohorts exposed to PHiD-CV (35/100,000 person-years) as compared with those exposed to PCV-7 (64/100,000 person-years; p=0.03). There was no breakthrough vaccine-type IPD case among children who had received ≥2 PHiD-CV doses for the primary series or a single PHiD-CV dose as a booster. There was also a statistically non-significant lower frequency of 19A and other non-vaccine types IPD cases in children exposed to 2+1 PHiD-CV doses as compared with those exposed to PCV-7.
  
  
  CONCLUSIONS
  Results are compatible with a high level of protection induced by PHiD-CV against IPD caused by homologous serotypes.
authors.affiliation: Department of Social and Preventive Medicine, Laval University, Quebec City, Canada. philippe.dewals@criucpq.ulaval.ca
authors.forename: Philippe
authors.initials: P
authors.lastname: De Wals
authors.forename: Brigitte
authors.initials: B
authors.lastname: Lefebvre
authors.forename: Fannie
authors.initials: F
authors.lastname: Defay
authors.forename: Geneviève
authors.initials: G
authors.lastname: Deceuninck
authors.forename: Nicole
authors.initials: N
authors.lastname: Boulianne
mesh_terms: D002675:Child, Preschool; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007115:Immunization Schedule; D007117:Immunization, Secondary; D007223:Infant; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D011792:Quebec; D014611:Vaccination / Q000706:statistics & numerical data*; D018074:Vaccines, Conjugate / Q000008:administration & dosage
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine; C547294:PHiD-CV vaccine; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate