Mark Jit
Modelling and Economics Unit
Health Protection Agency, London
Case study: Structural uncertainty in
human papillomavirus vaccinationmodelling
M Jit1,2, Y Choi1, N Gay1 and WJ Edmunds1,3
1Centre for Infections, Health Protection Agency2University of Birmingham3London School of Hygiene & Tropical Medicine
Outline
• Introduction to the problem
• Representing structural uncertainty
• Selecting optimal scenarios
• Presenting results
GardasilTM • Protects against HPV 6, 11, 16, 18.
• Doses at 0, 2, 6 months.
• Aluminium adjuvanted.
• Licensed widely, in use in several countries.
CervarixTM • Protects against HPV 16, 18.
• Doses at 0, 1, 6 months.
• AS04 adjuvanted.
• Licensed in Europe and Australia.
HPV vaccines
Female HPV prevalence in UK DNA studies
Epidemiological uncertainty
Progression and regression of HPV-related neoplastic states.
Duration of HPV infection.
Prevalence of anogenital warts among HPV 6 and 11 infected people.
Duration of vaccine protection.
Coverage of vaccination programme.
Uncertainty about disease burden
Cost and QoL impact of screening.
Cost and QoL impact of treating neoplasias, cancer, warts.
Accuracy of cytological screening and DNA testing.
Structural uncertainty
Natural regression of HPV-related neoplasias.
Existence of natural immunity to HPV.
Pattern of sexual partnerships between age and risk groups.
Vaccine protection against non-vaccine HPV types.
Sexual transmission stage
Changes in disease end points after
vaccine introduction
Type specific HPV prevalence by
cytological status (ARTISTIC trial)
Natural history stage
Progression and regression rates
Economic stage
Changes in the economic burden
(cost and quality of life)
Cytological status at time of screening
(Cervical screening programme)
Sexual partnership patterns
(Sexual lifestyle survey 2000)
Cost and quality of life data
(current literature)
Diagnosed anogenital warts
cases
(GP and GUM clinic returns)
Duration, QoL detriment of warts
episode
(York GUM study)
Types of models used
Sexual transmission stage
Changes in disease end points after
vaccine introduction
Natural history stage
Progression and regression rates
Economic stage
Changes in the economic burden
(cost and quality of life)
Jit M, Gay N, Soldan K, Choi YH, Edmunds WJ. Estimating progression rates for human papillomavirus infection from epidemiological data. Medical Decision Making (in press).
Sexual transmission stage
Changes in disease end points after
vaccine introduction
Natural history stage
Progression and regression rates
Economic stage
Changes in the economic burden
(cost and quality of life)
Economic stage
Changes in the economic burden
(cost and quality of life)
Sexual transmission stage
Changes in disease end points after
vaccine introduction
Natural history stage
Progression and regression rates
Economic stage
Changes in the economic burden
(cost and quality of life)
Sexual transmission stage
Changes in disease end points after
vaccine introduction
Natural history stage
Progression and regression rates
Natural history stage
Progression and regression rates
Economic stage
Changes in the economic burden
(cost and quality of life)
Sexual transmission stage
Changes in disease end points after
vaccine introduction
Natural history stage
Progression and regression rates
Economic stage
Changes in the economic burden
(cost and quality of life)
Sexual transmission stage
Changes in disease end points after
vaccine introduction
Natural history stage
Progression and regression rates
Economic stage
Changes in the economic burden
(cost and quality of life)
Sexual transmission stage
Changes in disease end points after
vaccine introduction
Sexual transmission stage
Changes in disease end points after
vaccine introduction
Natural history stage
Progression and regression rates
Economic stage
Changes in the economic burden
(cost and quality of life)
Sexual transmission stage
Changes in disease end points after
vaccine introduction
Natural history stage
Progression and regression rates
Economic stage
Changes in the economic burden
(cost and quality of life)
Jit M, Choi YH, Edmunds WJ. Economic evaluation of human papillomavirus vaccination in the United Kingdom. BMJ 2008; 337:a769.
Some relevant issues that were raised during this work
When is uncertainty structural rather than parametric?
How should different structural scenarios be weighed or selected?
How can we improve the computational efficiency of structural uncertainty analysis?
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