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The DECIDA study: Detailed Evaluation of a Childhood Immunisation Decision Aid
DOI 10.1186/ISRCTN72521372
ClinicalTrials.gov identifier
EudraCT number
Public title The DECIDA study: Detailed Evaluation of a Childhood Immunisation Decision Aid
Scientific title Supporting informed parental decision-making for MMR (the combined measles, mumps and rubella vaccine): Evaluation of a web-based decision aid
Acronym DECIDA
Serial number at source 08/H1311/23; UKCRN ID 4811
Study hypothesis 1. Parents receiving the web-based MMR decision aid will exhibit increased informed decision making over time relative to parents receiving an MMR leaflet alone.
2. The rate of vaccine uptake will be greater for parents receiving the web-based MMR decision aid compared to parents receiving an MMR leaflet alone.
Lay summary Background and study aims
UK parents continue to be concerned about the safety of the combined measles, mumps and rubella (MMR) vaccine. National uptake of the MMR vaccine is below the 95% needed to protect the population. Research shows that parents lack confidence in making an informed decision. Good methods to help parents make informed decisions are needed. We recently conducted a small study with 30 parents that explored their views on an MMR decision aid (web site). The next step was to test this decision aid with more parents. This study aimed to test whether a decision aid (web site) for MMR when compared with an MMR leaflet improved informed parental decision-making and increased uptake of the MMR vaccine. We also explored the financial cost of delivering the MMR decision aid versus the MMR leaflet, and asked parents and health professionals how useful they thought the decision aid and leaflet were.

Who can participate?
The aim was to recruit 576 first-time parents with a child aged 3 to 12 months being offered the first dose of the MMR vaccine. Parents were required to be registered with a participating GP practice in the north of England, have an email address and sufficient English language skills to participate.

What does the study involve?
The GP practices in the study were randomly allocated to one of three groups. Depending on the group their GP practice were put in, parents either received usual care for MMR from their GP practice (group 1) or usual care plus the MMR decision aid web site (group 2) or usual care plus an MMR leaflet (group 3). We measured parents’ informed decision-making in a questionnaire at the start of the study and then 2 weeks after the study had started. We also recorded the costs of delivering the MMR decision aid and leaflet and interviewed parents and doctors/nurses about their views on the MMR decision aid and leaflet.

What are the possible benefits and risks of participating?
This study helped us to better understand how parents make decisions about whether or not to immunise their child with the MMR vaccine. The MMR decision aid may help participants themselves and other parents in the future to make an informed decision about the MMR vaccine. There were no risks of taking part, just some demands on parents’ time.

Where is the study run from?
The study was run from the University of Leeds, UK. Other organisations involved in the study were the Health Protection Agency and NHS Leeds.

When is the study starting and how long is it expected to run for?
This study ran from September 2008 to the end of November 2010.

Who is funding the study?
The study was funded by the National Institute for Health Research (NIHR), Research for Patient Benefit Programme, UK.

Who is the main contact?
Dr Cath Jackson
Ethics approval Ethics approval was secured from York Research Ethics Committee on 4 April 2008 (Ref. 08/H1311/23)
Study design Three-arm cluster randomised controlled trial with qualitative and economic components
Countries of recruitment United Kingdom
Disease/condition/study domain Public health - childhood immunisation
Participants - inclusion criteria 1. All 312 GP practices within five Primary Care Trusts in the North of England were eligible.
2. First-time parents with a child aged 3 to 12 months being offered the first dose of the MMR vaccine were eligible.
3. Parents were required to have an email address and sufficient English language skills to participate.
Participants - exclusion criteria None
Anticipated start date 01/09/2008
Anticipated end date 30/11/2010
Status of trial Completed
Patient information material Not available in web format, please use the contact details below to request a patient information sheet
Target number of participants 576
Interventions The interventions were delivered at the individual parent level.
GROUP 1: Usual practice only (control)
Parents received the usual service provided by their GP practice. In England and Wales, parents of children registered with a GP receive an offer to have their child vaccinated for the first dose MMR at 12 to 13 months. Telephone interviews with participating GP practices indicated that usual practice included an appointment for the first dose MMR vaccination, a leaflet (usually ‘MMR the Facts’) and in some GP practices the offer of a consultation if the parent had concerns.
GROUP 2: MMR decision aid plus usual practice
Parents were sent by post the web link for the MMR decision aid with login instructions. They also continued to receive usual practice (described above) from their GP practice. The decision aid was a modified version of the Australian MMR decision aid. It can be accessed at www.leedsmmr.co.uk.
GROUP 3: MMR leaflet plus usual practice
Parents were sent the Health Scotland leaflet ‘MMR your questions answered’ and also received usual practice.
Primary outcome measure(s) Decisional conflict . This assessed a parent’s perception that their decision was informed in accordance with their values and can be acted upon. This 16-item validated scale has five sub-sections: informed, values clarity, support, uncertainty and effective decision. Scores range from 1 (no decisional conflict) to 5 (extremely high decisional conflict). Scores lower than two are associated with implementing informed decisions, higher scores are interpreted as delaying decisions or feeling unsure about their implementation.
Secondary outcome measure(s) 1. First dose MMR vaccination uptake data for children of participating parents (provided by GP practices)
2. Knowledge about MMR and the measles disease was measured using 11 multiple choice items.
3. MMR immunisation cognitions: The Theory of Planned Behaviour informed items to assess parents’ cognitions (attitude, subjective norm, perceived behavioural control) towards having their child immunised with MMR.
4. MMR immunisation trade-off beliefs were measured using a previously modified version of the Beliefs about Flu Vaccination Questionnaire to assess parents’ trade-off beliefs on vaccine necessity versus vaccine concerns for MMR . A single MMR immunisation ‘trade-off’ beliefs score was calculated. A positive score indicates that the parent perceives that necessity outweighs the concerns.
5. Anxiety was assessed by the short form State-Trait Anxiety Index.
6. Parents’ engagement with the decision aid or leaflet: Data were collected in the post-intervention questionnaire. Parents in the decision aid arm were asked ‘Did you use the MMR website?’ (Yes the whole website /Yes but only some of it /No). The time parents spent working through the decision aid was captured by Google analytics.
7. Parents in the leaflet arm were asked ‘Did you read the MMR leaflet?’ (Yes the whole leaflet /Yes but only some of it / No).
8. All parents were asked to report how long (minutes) they had spent looking at other information about MMR before or since their child was born.
9. Qualitative component: A sub-sample of parents and health professionals were interviewed about their views on the MMR decision aid or leaflet.
10. Eonomic component: Self-reported intended and actual numbers of parent contacts with health professionals and parent MMR-related expenditure were collected. Costs of delivering the MMR interventions (decision aid and leaflet) were calculated.
Sources of funding National Institute for Health Research, Research for Patient Benefit Programme (ref. PB-PG-0107-12048)
Trial website
Publications 2013 results in: http://www.ncbi.nlm.nih.gov/pubmed/24148574
Contact name Dr  Cath  Jackson
  Address York Trials Unit
Department of Health Sciences
ARRC Building
University of York
  City/town York
  Zip/Postcode YO10 5DD
  Country United Kingdom
  Tel 01904 32 1869
  Email cath.jackson@york.ac.uk
Sponsor University of Leeds (UK)
  Address Research Office
Worsley Building
Faculty of Medicine and Health
  City/town Leeds
  Zip/Postcode LS2 9JT
  Country United Kingdom
Date applied 03/06/2013
Last edited 29/10/2013
Date ISRCTN assigned 01/07/2013
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