Invasive pneumococcal diseases in birth cohorts vaccinated with PCV-7 and/or PHiD-CV in the province of Quebec, Canada

Department of Social and Preventive Medicine, Laval University, Quebec City, Canada
Vaccine (Impact Factor: 3.49). 08/2012; 30(45):6416-20. DOI: 10.1016/j.vaccine.2012.08.017
Source: PubMed

ABSTRACT 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.
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.
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 (64/100,000person-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.
Results are compatible with a high level of protection induced by PHiD-CV against IPD caused by homologous serotypes.

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