Vaccine decision making –are we asking the right questions? Discrete choice experiments https://www.meningitis.org/mrf-conference-2017

1. How do the public think we should prioritise
vaccination programmes?
Results from qualitative interviews and a
discrete choice experiment
Hannah Christensen
Gemma Lasseter, Hareth Al-Janabi, Caroline L Trotter,
Fran E Carroll
Health Protection Research Unit (HPRU) in Evaluation
of Intervention
27 November 2017
1MRF conference 2017

2. Is the current approach ok?
2

3. Are all QALYs equal?
3
=
?

4. The plan
• Identify factors which the population may consider
relevant in prioritising different vaccination
programmes
• Use a discrete choice experiment to determine
population preferences >> ‘weights’ that could be
used to prioritise vaccination programmes against
childhood diseases
4

5. Identifying factors the population think are
relevant when considering vaccine decisions
• Qualitative study
• 320 postal invites to adults in Bristol & S
Gloucestershire (200 March, +120 June 2016)
• 4 rounds of semi-structured interviews – thematic
analysis
• 21 interviews; 17♀ 4♂ age range 35-75+
5

6. 6
Age
Disease
severity
How
common
Social
group
Carer
impact
Side
effects
Herd
effects
Peace
of mind

infection
Factors

7. 7
“I think 1 year old or less is a vulnerable age group from
health wise and you know within considering possible death,
causes of death. Once they get a bit older, say two year olds,
they’re a bit more robust…”
Age

8. 8
“If it’s something that you can get over without any long-term
consequences then I’m not sure there’s a real need to be
vaccinated against it, but if it could result in death or long-
term health consequences then I think it’s a different case.”
Disease
severity

9. 9
[J]ust considering the impact on families or, children with
diseases that they could’ve been immunised against…it’s a
way of making policymakers think about the effects, because
they tend to think in financial terms, not necessarily in
effects on the family, on parents, on siblings and
psychological effects...depression, anxiety, self-harming, any,
any of those kind of things that can be triggered by extreme
circumstances.
Carer
impact

10. Using a DCE to determine population
preferences
• Developed DCE using 5 attributes from qualitative
study
• 32 questions split into 2 blocks – each person answers
16 questions
• Respondents given a scenario and asked to choose
between 2 vaccine options
• Representative sample of 2002 UK adults
10

11. 11
27 November 2017
“Imagine that you are a policy maker and that you have been given a limited
amount of money to fund a new vaccination programme in the UK. You have
been asked to choose between two different vaccination programmes, but
there is only enough money to fund one. Each vaccination programme costs
the same amount of money and will be given to same number of people (to
be exact 650,000 people). The vaccination programme is publically funded,
so there will be no charge for those people receiving the vaccine and it will
not be possible to buy the vaccine privately. The different vaccination
programmes have different benefits for the people vaccinated.”
Question 1
Vaccination Programme A Vaccination Programme B
Age group 12 to 17 years ≤1 year old
Disease severity Severe Moderate
How common Rare (65 people) Uncommon (650 people)
Carer impact Moderate Severe
Social group Socially advantaged Socially disadvantaged

I would choose
Vaccination Programme A

I would choose
Vaccination Programme B

12. DCE results
12
-0.800
-0.600
-0.400
-0.200
0.000
0.200
0.400
0.600
0.800
Vaccine A (left hand
side)
Vaccine B (right hand
side)
-0.800
-0.600
-0.400
-0.200
0.000
0.200
0.400
0.600
0.800
Very
common
Common Uncommon Rare
-0.800
-0.600
-0.400
-0.200
0.000
0.200
0.400
0.600
0.800
Mild Moderate Severe Very severe
-0.800
-0.600
-0.400
-0.200
0.000
0.200
0.400
0.600
0.800
Mild Moderate Severe Very severe
-0.800
-0.600
-0.400
-0.200
0.000
0.200
0.400
0.600
0.800
Advantaged Disadvantaged
Age group How common
Carer impact
Disease severity
Social (dis)ad Alternative
-0.800
-0.600
-0.400
-0.200
0.000
0.200
0.400
0.600
0.800
≤1 year old 2 to 11
years
12 to 17
years
18 years+
Vaccine A
(left hand side)
CoefficientCoefficient
Vaccine B
(right hand side)

13. Conclusions
• The UK general public do have preferences for
characteristics relevant to vaccine decision making
• Early evidence to suggest these preferences differ
from ‘weight’ currently used
• Future CE analysis should consider these population
preference ‘weights’
13

14. Acknowledgements
14
With thanks to the individuals who took part in
the qualitative interviews and DCE survey.
This study was funded by the Meningitis
Research Foundation.
HC is supported by the NIHR Health Protection
Research Unit in Evaluation of Interventions at
University of Bristol. The views expressed are
those of the author(s) and not necessarily
those of the NHS, the NIHR, the Department of
Health or Public Health England.
Research team
Dr Gemma Lasseter
University of Bristol
Dr Hareth Al-Janabi
University of Birmingham
Dr Caroline L Trotter
University of Cambridge
Dr Fran E Carroll
Royal College of Obstetricians and
Gynaecologists