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Type: Journal article
Title: A randomised controlled trial to compare opt-in and opt-out parental consent for childhood vaccine safety surveillance using data linkage: study protocol
Author: Berry, J.
Ryan, P.
Braunack-Mayer, A.
Duszynski, K.
Xafis, V.
Gold, M.
Citation: Trials, 2011; 12(1):1-10
Publisher: BioMed Central Ltd.
Issue Date: 2011
ISSN: 1745-6215
Statement of
Jesia G Berry, Philip Ryan, Annette J Braunack-Mayer, Katherine M Duszynski, Vicki Xafis, Michael S Gold, the Vaccine Assessment Using Linked Data (VALiD) Working Group
Abstract: Background: The Vaccine Assessment using Linked Data (VALiD) trial compared opt-in and opt-out parental consent for a population-based childhood vaccine safety surveillance program using data linkage. A subsequent telephone interview of all households enrolled in the trial elicited parental intent regarding the return or non-return of reply forms for opt-in and opt-out consent. This paper describes the rationale for the trial and provides an overview of the design and methods. Methods/Design: Single-centre, single-blind, randomised controlled trial (RCT) stratified by firstborn status. Mothers who gave birth at one tertiary South Australian hospital were randomised at six weeks post-partum to receive an opt-in or opt-out reply form, along with information explaining data linkage. The primary outcome at 10 weeks post-partum was parental participation in each arm, as indicated by the respective return or non-return of a reply form (or via telephone or email response). A subsequent telephone interview at 10 weeks post-partum elicited parental intent regarding the return or non-return of the reply form, and attitudes and knowledge about data linkage, vaccine safety, consent preferences and vaccination practices. Enrolment began in July 2009 and 1,129 households were recruited in a three-month period. Analysis has not yet been undertaken. The participation rate and selection bias for each method of consent will be compared when the data are analysed. Discussion: The VALiD RCT represents the first trial of opt-in versus opt-out consent for a data linkage study that assesses consent preferences and intent compared with actual opting in or opting out behaviour, and socioeconomic factors. The limitations to generalisability are discussed.
Keywords: Vaccine Assessment Using Linked Data (VALiD) Working Group
Immunization Schedule
Data Collection
Population Surveillance
Health Care Surveys
Medical Record Linkage
Single-Blind Method
Product Surveillance, Postmarketing
Health Knowledge, Attitudes, Practice
Health Behavior
Research Design
Parental Consent
Socioeconomic Factors
Immunization Programs
South Australia
Description: Extent: 10p.
Rights: © 2011 Berry et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
DOI: 10.1186/1745-6215-12-1
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