Parainfluenza Virus

For the purposes of the calculations in this report, the committee estimated that there are 2.5 million cases of parainfluenza virus (PIV) infection each year in the United States in children under 2 years of age. An additional 3.5 million infections occur in people greater than 2 years of age (25% of those in people 65 years of age or older). It is also assumed that there are 300 deaths per year in children 2 years of age and under and 140 deaths in people 65 years of age and older due to PIV disease.

For the purposes of the calculation in this report, the committee assumed that PIV disease manifests as either a mild infection such as pharyngitis or otitis media, croup, or bronchiolitis/pneumonia. It was assumed that in children 2 years of age and under, the proportion of infections manifesting as those 3 disease scenarios is 70%, 20%, and 10% respectively. For people 2 years of age and older, it was assumed that the distribution is 90% as pharyngitis and 10% as bronchiolitis and pneumonia. The health utility index associated with PIV disease ranges from 0.9 (7 days of pharyngitis) to .5 (7 days of either croup or bronchiolitis). See Table A19–1.

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Vaccines for the 21st Century: A Tool for Decisionmaking
APPENDIX 19
Parainfluenza Virus
DISEASE BURDEN
Epidemiology
For the purposes of the calculations in this report, the committee estimated that there are 2.5 million cases of parainfluenza virus (PIV) infection each year in the United States in children under 2 years of age. An additional 3.5 million infections occur in people greater than 2 years of age (25% of those in people 65 years of age or older). It is also assumed that there are 300 deaths per year in children 2 years of age and under and 140 deaths in people 65 years of age and older due to PIV disease.
Disease Scenarios
For the purposes of the calculation in this report, the committee assumed that PIV disease manifests as either a mild infection such as pharyngitis or otitis media, croup, or bronchiolitis/pneumonia. It was assumed that in children 2 years of age and under, the proportion of infections manifesting as those 3 disease scenarios is 70%, 20%, and 10% respectively. For people 2 years of age and older, it was assumed that the distribution is 90% as pharyngitis and 10% as bronchiolitis and pneumonia. The health utility index associated with PIV disease ranges from 0.9 (7 days of pharyngitis) to .5 (7 days of either croup or bronchiolitis). See Table A19–1.

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Vaccines for the 21st Century: A Tool for Decisionmaking
Table A19–1 Disease Scenarios for Parainfluenza Virus Infection
% of Cases
Committee HUI Values
Duration (years)
Upper Respiratory
70.00%
pharyngitis, otitis media
0.90
0.0192 (7 days)
Croup
19.20%
outpatient only
0.75
0.0274 (10 days)
Croup
0.80%
inpatient
0.50
0.0192 (7 days)
outpatient
0.75
0.0082 (3 days)
Bronchiolitis/pneumonia
9.60%
outpatient only
0.75
0.0274 (10 days)
Bronchiolitis/pneumonia
0.40%
inpatient
0.50
0.0192 (7 days)
outpatient
0.75
0.0082 (3 days)
Upper Respiratory
90.00%
0.90
0.0192 (7 days)
Bronchiolitis/pneumonia
10.00%
0.75
0.0274 (10 days)
Upper Respiratory
90.00%
0.90
0.0192 (7 days)
Bronchiolitis/pneumonia
9.60%
0.75
0.0274 (10 days)
Bronchiolitis/pneumonia
0.40%
inpatient
0.50
0.0192 (7 days)
outpatient
0.75
0.0082 (3 days)
COST INCURRED BY DISEASE
Table A19–2 summarizes the health care costs incurred by PIV infections. For the purposes of the calculations in this report, it was assumed that all children 2 years of age and under with PIV disease receive medical treatment. It was assumed that only 50% of people between the ages of 2 and 64 receive treatment for PIV disease. It was also assumed that only 50% of people 65 years of age and older receive treatment for mild (requiring only outpatient treatment if treated) pharyngitis and bronchiolitis. A small number of people age 65 years of age and older are hospitalized for bronchiolitis and pneumonia.
Pharyngitis, otitis media, croup, and outpatient treatment of bronchiolitis/pneumonia were assumed to be associated with physician visits, diagnostics and medications. The more serious disease incurred more visits to the physician. Hospitalization costs are included for the small number of people with PIV disease who require it.

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Vaccines for the 21st Century: A Tool for Decisionmaking
Table A19–2 Costs of Care for Parainfluenza Virus Infection
% with Care
Cost per Unit
Units per Case
Form of Treatment
AGE<2
Upper Respiratory
pharyngitis, otitis media
100%
$50
1.0
physician a
100%
$50
1.0
diagnostic a
100%
$50
1.0
medication b
Croup
outpatient only
100%
$50
2.0
physician a
100%
$50
1.0
diagnostic a
100%
$50
1.0
medication b
inpatient
100%
$3000
1.0
hospitalization
100%
$50
2.0
physician a
100%
$50
1.0
diagnostic a
100%
$50
1.0
medication b
Bronchiolitis/pneumonia
outpatient only
100%
$50
2.0
physician a
100%
$50
1.0
diagnostic a
100%
$50
1.0
medication b
Bronchiolitis/pneumonia
inpatient
100%
$4000
1.0
hospitalization
100%
$50
2.0
physician a
100%
$50
1.0
diagnostic a
100%
$50
1.0
medication b
AGE 2–64
Upper Respiratory
pharyngitis, otitis media
50%
$50
1.0
physician a
50%
$50
1.0
diagnostic a
50%
$50
1.0
medication b
Bronchiolitis/pneumonia
outpatient only
50%
$50
2.0
physician a
50%
$50
1.0
diagnostic a
50%
$50
1.0
medication b
AGE 65+
Upper Respiratory
pharyngitis, otitis media
50%
$50
1.0
physician a
50%
$50
1.0
diagnostic a
50%
$50
1.0
medication b
Bronchiolitis/pneumonia
outpatient only
50%
$50
2.0
physician a
50%
$50
1.0
diagnostic a
50%
$50
1.0
medication b
Bronchiolitis/pneumonia
inpatient
100%
$4000
1.0
hospitalization
100%
$50
2.0
physician a
100%
$50
1.0
diagnostic a
100%
$50
1.0
medication b

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Vaccines for the 21st Century: A Tool for Decisionmaking
VACCINE DEVELOPMENT
The committee assumed that it will take 7 years until licensure of a PIV vaccine and that $300 million needs to be invested for licensure for infants and another $360 million for a vaccine for pregnant women. Table 4–1 summarizes vaccine development assumptions for all vaccines considered in this report.
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 all infants and all primiparas. It was assumed that 90% of infants and targeted pregnant women would receive 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% effectiveness were accepted. Table 4–1 summarizes vaccine program assumptions for all vaccines considered in this report.
RESULTS
If a vaccine program for PIV were implemented today and the vaccine were 100% efficacious and utilized by 100% of the target population, the annualized present value of the QALYs gained would be 21,000. 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 10,000.
If a vaccine program for PIV 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 $580 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 $275 million.
If a vaccine program for PIV 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 $1 billion. Using committee assumptions of less-than-ideal efficacy and utilization and including time and

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monetary costs until a vaccine program is implemented, the annualized present value of the program cost would be $640 million.
Using committee assumptions of time and costs until licensure, the fixed cost of vaccine development has been amortized and is $19.8 million for a PIV vaccine.
If a vaccine program were implemented today and the vaccine was 100% efficacious and utilized by 100% of the target population, the annualized present value of the cost per QALY gained is $20,000. 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 $38,000. If only 10% of primiparas utilized the vaccine, the annualized present value of the cost per QALY gained is $50,000.
See Chapters 4 and 5 for details on the methods and assumptions used by the committee for the results reported.
READING LIST
Hall CB. Parainfluenza Viruses. In: Textbook of Pediatric Infectious Diseases. RD Feigin and JD Cherry eds. Philadelphia, PA: WB Saunder Company, 1992, pp. 1613–1624.
Henrickson K, Ray R, Belshe R. Parainfluenza Viruses. In: Principles and Practice of Infectious Diseases. GL Mandell, JE Bennett, Dolin R eds. New York, NY: Churchill Livingstone, 1995, pp. 1489–1496.
Karron RA, Wright PF, Newman FK, et al. A Live Human Parainfluenza Type 3 Virus Vaccine is Attenuated and Immunogenic in Healthy Infants and Children. The Journal of Infectious Diseases 1995; 172:1445–1450.
Ventura SJ, Martin JA, Mathews TJ, et al. Advance Report of Final Natality Statistics, 1994. Monthly Vital Statistics Report 1996; 44.

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