Economic Evaluations of Hepatitis B and Pneumococcal Conjugate Vaccines

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Economic Evaluations of Hepatitis B and
Pneumococcal Conjugate Vaccines

• Lesley Tilson, PhD
• National Centre for Pharmacoeconomics
• Summer Scientific Meeting, RCPI 30th May 2007

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Outline

• Background Pharmacoeconomics.
• Economic evaluation of of a Universal Infant
  Hepatitis B Vaccination Strategy.
• Economic Evaluation of a Universal Infant
  Pneumococcal Conjugate Vaccination Strategy.

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Pharmacoeconomics

• Pharmacoeconomics is that branch of health
  economics that focuses upon the costs and
  benefits of drug therapy.
• Resources are scarce.
• Increased emphasis on value for money.
• Aim for maximum health impact from a given
  budget.
• Definition The comparative analysis of
  alternative courses of action in terms of BOTH
  their costs and health outcomes.

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Results are Expressed as an Incremental Cost
Effectiveness Ratio (ICER)
Cost A Cost BEffect A Effect B or Cost
Effect
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Lower Effectiveness
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Economic Evaluation of a Universal Infant
Hepatitis B Vaccination Strategy
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Hepatitis B Virus (HBV) Infection

• 1997 - the WHO recommended all member countries
  include hepatitis B vaccine in national
  immunisation programmes.
• The UK, Ireland, Scandinavian countries and the
  Netherlands have not yet introduced universal
  immunisation against HBV infection.
• Current immunisation policy in Ireland based on
  targeting identifiable risk groups for
  vaccination.

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HBV Infection in Ireland

• Low prevalence of HBV infection in Ireland.
• Notifications have increased dramatically in
  recent years (30 in 1997 to gt900 in 2005).
• Changing demography.
• This raises the question of whether a universal
  vaccination programme should be introduced in
  Ireland.

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Number of Cases of HBV Infection Notified in
Ireland, 1990 to 2005
1000
900
800
700
600
500
Number of notifications
400
300
200
100
0
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
Year
Source HPSC
The number of HBV notifications increased
dramatically between 1997 (n30) and 2005 (n900)
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Objective of Study

• To evaluate the incremental costs and benefits of
  universal infant vaccination vs the current
  hepatitis B vaccination strategy.
• Vaccination strategies
• 1. Selective strategy Administration of a
  monovalent hepatitis B vaccine to high-risk
  infants.
• 2. Universal infant strategy Administration of
  a multivalent 6 in 1 vaccine to all infants.

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Description of Model

• Perspective of the study HSE.
• Only direct medical costs included.
• Time horizon 80 years.
• Future costs and health benefits discounted at
  3.5 per annum.
• Costs and benefits compared in universal and
  selective vaccination arms.

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Cost Effectiveness Model of Hepatitis B
Vaccination Strategies universal infant vs
selective strategy
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Markov Model of Hepatitis B Infection

• Cohort of individuals progress through the
  following transition states
• Susceptible
• Recovery/immunity
• Chronic HBV (chronic carrier phase)
• Chronic HBV (chronic active hepatitis phase)
• Cirrhosis
• Hepatocellular carcinoma
• Death

Acute infection
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Sensitivity Analysis

• To allow for uncertainty by altering the values
  of key variables.
• One way sensitivity analysis each parameter is
  varied one at a time to investigate the impact on
  the ICER.

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One-Way Sensitivity Analysis

• Cost of vaccination.
• Risk of acquiring acute HBV infection.
• Direct medical costs of HBV infection.
• Uptake of selective vaccination.
• Uptake of universal vaccination.
• Seroprotection from vaccination.

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Base Case ResultsOver the lifetime of a birth
cohort of infants the model estimates
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Base Case ResultsCost effectiveness

• Incremental Cost-Effectiveness Ratio (ICER) of
  universal infant vaccination strategy compared to
  current selective strategy.
• 37,018 / life year gained (LYG)
• Base case scenario Incidence of acute HBV 8.4
  per 100,000.
• Price per dose of 6 in 1 vaccine 29.

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One-Way Sensitivity Analysis Cost of
universal vaccination
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Two-Way Sensitivity AnalysisIncidence of HBV
infection and cost of universal vaccination
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One-Way Sensitivity Analyses
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Conclusion

• Results sensitive to
• Risk of acquiring acute HBV infection.
• Cost of the universal vaccination programme.
• At an incidence of acute HBV infection of 8.4 per
  100,000 and a price per dose of 29 for the 6 in
  1 vaccine, the ICER
• 37,018/LYG.

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Economic Evaluation of a Universal Infant
Pneumococcal Conjugate Vaccination Strategy
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Pneumococcal Infection

• Invasive Pneumococcal Disease (IPD) meningitis
  septicaemia.
• Non-invasive disease pneumonia otitis media.
• Incidence of IPD in children lt5 years -
  24.1/100,000.
• 7-valent conjugate vaccine (PCV7, Prevenar?)
  offers protection against pneumococcal infection.
• Evidence of herd immunity effect.

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Annual Incidence of IPD Reported in Ireland in
2005 (EARSS data)
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Objective

• To estimate the cost-effectiveness of routine
  vaccination of children in Ireland with PCV7
  compared with no vaccination.

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Description of Model

• Perspective of the study HSE.
• Duration of vaccine protection 5 years.
• Indirect effect of vaccine Assume vaccine also
  confers protection on adults for 1 year herd
  immunity model.
• Future costs and health benefits discounted at
  3.5 per annum.

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Base Case Model

• Two infant cohorts (vaccinated and unvaccinated)
  may develop the following infections
• Pneumococcal meningitis
• Pneumococcal septicaemia
• All-cause pneumonia
• All-cause Acute Otitis Media (AOM)

Long term complications
Expected costs and benefits in the two cohorts
are compared.
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One-Way Sensitivity Analysis

• Cost of PCV7 vaccine.
• Duration onset of protection.
• Vaccine efficacy.
• Vaccine uptake.
• Incidence of pneumococcal infection.
• Direct medical costs.
• Cost of long-term complications.

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Summary of Key Results

• ICER for base case model (vaccine effective in
  infant cohort only)
• 98,279/LYG
• ICER when effect of herd immunity included
• 5,913/LYG

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Summary of Key Findings from Sensitivity Analysis

• The model is sensitive to the following
  parameters
• Effect of herd immunity.
• Cost of PCV7 vaccine.
• Onset and duration of protection.
• Vaccine efficacy.
• Incidence of pneumococcal infection.

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Acknowledgements

• Dr Lelia Thornton, Dr Suzanne Cotter, Dr Darina
  OFlanagan - Health Protection Surveillance
  Centre.
• Dr Howard Johnson - Health Intelligence, National
  Population Health Directorate, HSE.
• Dr Karina Butler, Dr John Fitzsimmons, Dr Fiona
  OHare - Our Ladys Childrens Hospital, Crumlin
  The Childrens University Hospital, Temple
  Street.
• Dr Suzanne Norris Consultant Hepatologist, SJH.
• Dr Kathleen Bennett Statistician.
• Dr Brenda Corcoran, Cliona Kiersey HSE National
  Immunisation Office.
• Dr Mary Cafferkey Rotunda Hospital.
• Dr Julie Heslin HSE South Eastern Region.