title: Impact of conjugate 7-valent vaccination in Belgium: addressing methodological challenges.
abstract: In Belgium, the 7-valent pneumococcal conjugate vaccine (PCV7) was introduced into the national schedule in 2007. The early impact of PCV7 vaccination on paediatric invasive disease was estimated by comparing pre- and post-vaccination incidence from national surveillance. In children <2 year-olds, vaccine-serotype incidence declined by 96% but non-vaccine-types increased 2-3-fold. Overall invasive disease decreased by 23-46%, depending on adjustment for under-reporting and pre-vaccine trends. Non-vaccine-types 1 and 19A had increased before PCV7 use, suggesting the contribution of other factors. Estimation of PCV7 impact comparing pre- and post-vaccination data should adjust for pre-vaccine trends, and serotype dynamics need further exploration.
authors.affiliation: Scientific Institute of Public Health, Brussels, Belgium. germaine@skynet.be
authors.forename: Germaine
authors.initials: G
authors.lastname: Hanquet
authors.forename: Tinne
authors.initials: T
authors.lastname: Lernout
authors.forename: Anne
authors.initials: A
authors.lastname: Vergison
authors.forename: Jan
authors.initials: J
authors.lastname: Verhaegen
authors.forename: Esther
authors.initials: E
authors.lastname: Kissling
authors.forename: David
authors.initials: D
authors.lastname: Tuerlinckx
authors.forename: Anne
authors.initials: A
authors.lastname: Malfroot
authors.forename: Béatrice
authors.initials: B
authors.lastname: Swennen
authors.forename: Martine
authors.initials: M
authors.lastname: Sabbe
mesh_terms: D001530:Belgium / Q000453:epidemiology; D002675:Child, Preschool; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007115:Immunization Schedule; D015994:Incidence; D011008:Pneumococcal Infections / Q000453:epidemiology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology; D011159:Population Surveillance; D013296:Streptococcus pneumoniae / Q000302:isolation & purification; D014611:Vaccination / Q000706:statistics & numerical data*; D018074:Vaccines, Conjugate / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate