title: Assessing vaccination coverage in infants, survey studies versus the Flemish immunisation register: achieving the best of both worlds.
abstract: Infant immunisation coverage in Flanders, Belgium, is monitored through repeated coverage surveys. With the increased use of Vaccinnet, the web-based ordering system for vaccines in Flanders set up in 2004 and linked to an immunisation register, this database could become an alternative to quickly estimate vaccination coverage. To evaluate its current accuracy, coverage estimates generated from Vaccinnet alone were compared with estimates from the most recent survey (2012) that combined interview data with data from Vaccinnet and medical files. Coverage rates from registrations in Vaccinnet were systematically lower than the corresponding estimates obtained through the survey (mean difference 7.7%). This difference increased by dose number for vaccines that require multiple doses. Differences in administration date between the two sources were observed for 3.8-8.2% of registered doses. Underparticipation in Vaccinnet thus significantly impacts on the register-based immunisation coverage estimates, amplified by underregistration of administered doses among vaccinators using Vaccinnet. Therefore, survey studies, despite being labour-intensive and expensive, currently provide more complete and reliable results than register-based estimates alone in Flanders. However, further improvement of Vaccinnet's completeness will likely allow more accurate estimates in the nearby future.
authors.affiliation: Centre for the Evaluation of Vaccination, Vaccine & Infectious Disease Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium. Electronic address: tessa.braeckman@uantwerpen.be.
authors.forename: Tessa
authors.initials: T
authors.lastname: Braeckman
authors.affiliation: Centre for the Evaluation of Vaccination, Vaccine & Infectious Disease Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium.
authors.forename: Tinne
authors.initials: T
authors.lastname: Lernout
authors.affiliation: Flemish Agency for Care and Health, Infectious Disease Control and Vaccinations, Belgium.
authors.forename: Geert
authors.initials: G
authors.lastname: Top
authors.affiliation: Flemish Agency for Care and Health, Infectious Disease Control and Vaccinations, Belgium.
authors.forename: Annick
authors.initials: A
authors.lastname: Paeps
authors.affiliation: Department of Public Health and Primary Care, Centre for Youth Health Care, KU Leuven, Belgium.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Roelants
authors.affiliation: Department of Public Health and Primary Care, Centre for Youth Health Care, KU Leuven, Belgium.
authors.forename: Karel
authors.initials: K
authors.lastname: Hoppenbrouwers
authors.affiliation: Centre for the Evaluation of Vaccination, Vaccine & Infectious Disease Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium.
authors.forename: Pierre
authors.initials: P
authors.lastname: Van Damme
authors.affiliation: Centre for the Evaluation of Vaccination, Vaccine & Infectious Disease Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium; Fund of Scientific Research (FWO), Belgium.
authors.forename: Heidi
authors.initials: H
authors.lastname: Theeten
mesh_terms: D001530:Belgium; D019992:Databases as Topic; D005260:Female; D006801:Humans; D007223:Infant; D020407:Internet; D008297:Male; D012042:Registries; D014611:Vaccination / Q000706:statistics & numerical data*
keywords: Flanders (Belgium); Immunisation coverage; Immunisation register; Infant; Survey study