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Vaccines for the 21st Century: A Tool for Decisionmaking
APPENDIX 8
Hepatitis C
The hepatitis C virus (HCV) is the major cause of parenteral non-A, non-B hepatitis. A chronic infection is usually asymptomatic even when liver damage is seen in biopsy. Eventually, the chronic infection can lead to cirrhosis and hepatocellular carcinoma. The prevalence of HCV is significantly greater in intravenous-drug users than in blood donors. At least half of the patients who have previously been diagnosed with posttransfusion non-A, non-B hepatitis have tested positive for HCV antibodies. Some countries, such as Japan, have a higher frequency of HCV infection, which is reflected in the high frequency of hepatocellular carcinoma.
DISEASE BURDEN
Epidemiology
For the purposes of the calculations in this report, the committee estimated that there are 150,000 new infections with HCV every year in the United States. It is assumed that all new infections occur in people between 15 and 54 years of age.
See Appendix 28 for more information.
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Disease Scenarios
For the purposes of the calculation in this report, the committee assumed that 30% of people with HCV infection experience only an acute and mild disease lasting approximately 2 weeks. The health utility index (HUI) associated with this illness is .9. It was assumed that 50% of people with HCV infection experience lifelong but very mild intermittent illness (HUI of .97). It was assumed that 7% of HCV infections lead to chronic hepatitis associated with a rapid, progressive course leading to death within 7 years of infection. The remaining 13% of HCV infections were associated with the mortality from cirrhosis and liver failure 25 years after infection and cirrhosis and liver cancer 30 years after infection. See Table A8–1.
COST INCURRED BY DISEASE
Table A8–2 summarizes the health care costs incurred by HCV infections. For the purposes of the calculations in this report, it was assumed that a relatively small fraction of patients experiencing mild symptoms of acute hepatitis seek medical treatment. Hospitalization and related costs are included for a very few patients. For the 50% of patients with HCV who have lifelong, uncomplicated, mild hepatitis, it was assumed that, on average, 10% of these people see a physician for illness associated (but unrecognized in many cases) with the HCV infection.
HCV infections associated with a chronic course but leading to severe liver disease was associated with 20 and 30 years of treatment for low grade symptoms (diagnosed as HCV-related or not). 10% of patients visit a specialist every other year. The 4-year symptomatic phase was associated with quarterly specialist visits, 2 hospitalizations, and a biopsy (for 10% of the patients). The year spent in terminal cirrhosis, liver failure, or liver cancer was assumed to be associated with a hospitalization and monthly specialist visits.
The rapid, progressive course of HCV disease was assumed to be associated with antiviral medication, bimonthly specialist visits, 2 extensive diagnostics per year for 6 years, and 1 hospitalization during that time period. The final year of life was assumed to be associated with hospitalization and monthly visits to a specialist.
VACCINE DEVELOPMENT
The committee assumed that it will take 15 years until licensure of an HCV vaccine and that $360 million needs to be invested. Table 4–1 summarizes vaccine development assumptions for all vaccines considered in this report.
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Table A8–1 Disease Scenarios for Hepatitis C Infection
No. of Cases
% of Cases
Committee HUI Values
Duration (years)
Total Cases (new symptomatic and asymptomatic infections)
150,000
Acute Hepatitis
45,000
30%
jaundice, malaise, etc.
0.90
0.0384 (2 weeks)
Chronic Hepatitis: Slow course—No complications
75,600
50%
low-grade symptoms
0.97
20.3164 (quality-adjusted life expectancy at onset). 43.3484 (unadjusted life expectancy at onset)
Chronic Hepatitis: Slow course—Cirrhosis to liver failure
3,780
3%
low-grade symptoms
0.97
20.0000
symptomatic phase
0.90
4.0000
terminal cirrhosis; liver failure
0.59
1.0000
premature death
0.00
12.3902 (quality-adjusted life expectancy at onset+25 years). 21.3870 (unadjusted life expectancy at onset+25 years)
Chronic Hepatitis: Slow course—Cirrhosis to carcinoma
15,120
10%
low-grade symptoms
0.97
30.0000
symptomatic phase
0.90
4.0000
terminal carcinoma
0.59
1.0000
premature death
0.00
8.7664 (quality-adjusted life expectancy at onset +35 years). 14.4048 (unadjusted life expectancy at onset+35 years)
Chronic Hepatitis: Rapid, progressive course
10,500
7%
liver failure: symptomatic
0.90
6.0000
liver failure: terminal
0.59
1.0000
premature death
0.00
18.5549 (quality-adjusted life expectancy at onset+7 years). 36.8422 (unadjusted life expectancy at onset+7 years)
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Table A8–2 Health Care Costs Associated with Hepatitis C Infection
Duration (years)
% with Care
Cost per Unit
Units per Case
Form of Treatment (per year for chronic phases)
Acute Hepatitis
0.0384
20%
$50
2.0
physician a
0.0384
5%
$2,000
1.0
hospitalization
0.0384
5%
$100
2.0
physician b
0.0384
5%
$100
2.0
diagnostics b
0.0384
5%
$150
1.0
medication c
Chronic Hepatitis: Slow course—No complications
low-grade symptoms
43.3484
10%
$50
1.0
physician a
Chronic Hepatitis: Slow course—Cirrhosis to liver failure
low-grade symptoms
20.0000
10%
$100
0.5
physician visit
symptomatic phase
4.0000
100%
$100
4.0
physician b
4.0000
10%
$12,000
0.25
biopsy (1 in 4 years)
4.0000
100%
$5,000
0.5
hospitalization (1 in 2 years)
terminal cirrhosis; liver failure
1.0000
100%
$5,000
1.0
hospitalization
1.0000
100%
$100
12.0
physician b
Chronic Hepatitis: Slow course—Cirrhosis to carcinoma
low-grade symptoms
30.0000
10%
$100
0.5
physician a
symptomatic phase
4.0000
10%
$12,000
0.25
biopsy
4.0000
100%
$100
4.0
physician b
4.0000
100%
$5,000
0.5
hospitalization
terminal carcinoma
1.0000
100%
$5,000
1.0
hospitalization
1.0000
100%
$100
12.0
physician b
Chronic Hepatitis: Rapid, progressive course
liver failure: symptomatic
6.0000
100%
$150
12.0
medication c
6.0000
100%
$100
6.0
physician b
6.0000
100%
$1,000
2.0
diagnostics
6.0000
100%
$12,000
0.2
hospitalization
liver failure: terminal
1.0000
100%
$5,000
1.0
hospitalization
1.0000
100%
$100
12.0
physician b
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VACCINE PROGRAM CONSIDERATIONS
Target Population
For the purposes of the calculations in this report, it is assumed that the target population for this vaccine is the annual birth cohort. It was assumed that 90% of the target population would utilize the vaccine.
Vaccine Schedule, Efficacy, and Costs
For the purposes of the calculations in this report, it was estimated that this vaccine would cost $50 per dose and that administration costs would be $10 per dose. Default assumptions of a 3-dose series and 75% efficacy were accepted. Table 4–1 summarizes vaccine program assumptions for all vaccines considered in this report.
RESULTS
If a vaccine program for HCV were implemented today and the vaccine was 100% efficacious and utilized by 100% of the target population, the annualized present value of the QALYs gained would be 110,000. Using committee assumptions of less-than-ideal efficacy and utilization and including time and monetary costs until a vaccine program is implemented, the annualized present value of the QALYs gained would be 41,000.
If a vaccine program for HCV were implemented today and the vaccine was 100% efficacious and utilized by 100% of the target population, the annualized present value of the health care costs saved would be $ 180 million. Using committee assumptions of less-than-ideal efficacy and utilization and including time and monetary costs until a vaccine program is implemented, the annualized present value of the health care costs saved would be $67.9 million.
If a vaccine program for HCV were implemented today and the vaccine was 100% efficacious and utilized by 100% of the target population, the annualized present value of the program cost would be $720 million. Using committee assumptions of less-than-ideal efficacy and utilization and including time and monetary costs until a vaccine program is implemented, the annualized present value of the program cost would be $360 million.
Using committee assumptions of time and costs until licensure, the fixed cost of vaccine development has been amortized and is $10.8 million for a HCV vaccine.
If a vaccine program were implemented today and the vaccine were 100% efficacious and utilized by 100% of the target population, the annualized present
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value of the cost per QALY gained is $5,000. If the target population was all 12-year-olds, the annualized present value of the cost per QALY gained is $3,000. Using committee assumptions of less-than-ideal utilization and including time and monetary costs until a vaccine program is implemented, the annualized present value of the cost per QALY gained is $7,400. If the target population was all 12-year-olds (assuming 50% utilization), the annualized present value of the cost per QALY gained is $4,000.
See Chapters 4 and 5 for details on the methods and assumptions used by the committee for the results reported.
READING LIST
Bhandari BN, Wright TL. Hepatitis C: An Overview. Annual Review of Medicine 1995; 46:309–317.
Lemon SM, Brown EA. Hepatitis C Virus. In: Principles and Practice of Infectious Diseases. GL Mandell, JE Bennett, Dolin R eds. New York, NY: Churchill Livingstone, 1995, pp. 1474–1486.
Representative terms from entire chapter:
target population
