title: Indirect effect of conjugate pneumococcal vaccination in a 2+1 dose schedule.
abstract: In 2006, the heptavalent pneumococcal conjugate vaccine (PCV7) was introduced in the Norwegian Childhood Vaccination Programme in a 2+1 dose schedule; immunisations are administered at 3, 5 and 12 months. Changes in invasive pneumococcal disease in all ages from the baseline years 2004-2005 to 2008 were assessed, focusing on the indirect effect in the unvaccinated population. Following the introduction of PCV7, incidence rates of IPD caused by vaccine serotypes declined across all age groups, the decline being statistically significant for the age groups <5 years, 5-19 years, 40-64 years and > or = 65 years. In the unvaccinated population aged > or = 5 years the incidence rate of IPD caused by PCV7 serotypes declined by 48% from 12.34 cases/100,000 population to 6.44 cases/100,000 population, accounting for 74% of prevented cases of IPD in 2008. Among the adults aged > or = 65 years the incidence rate of IPD caused by serotypes not included in PCV7 increased. No vaccine failure was identified, indicating a very high effectiveness of the 2+1 dose schedule vaccination programme.
authors.affiliation: Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway. Electronic address: didrik.frimann.vestrheim@fhi.no.
authors.forename: Didrik F
authors.initials: DF
authors.lastname: Vestrheim
authors.affiliation: Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: E Arne
authors.initials: EA
authors.lastname: Høiby
authors.affiliation: Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Marianne R
authors.initials: MR
authors.lastname: Bergsaker
authors.affiliation: Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Karin
authors.initials: K
authors.lastname: Rønning
authors.affiliation: Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Ingeborg S
authors.initials: IS
authors.lastname: Aaberge
authors.affiliation: Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Dominique A
authors.initials: DA
authors.lastname: Caugant
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007115:Immunization Schedule; D007117:Immunization, Secondary / Q000379:methods*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D014611:Vaccination / Q000379:methods*; D055815:Young Adult
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines