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Vaccines for the 21st Century: A Tool for Decisionmaking (2000)

Chapter: Appendix 25: Streptococcus, Group B

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Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×

APPENDIX 25
Streptococcus, Group B

DISEASE BURDEN

Epidemiology

For the purposes of the calculations in this report, the committee estimated that there are approximately 7,000 new infections with streptococcus, group B (GBS) and 430 deaths in infants and 4,000 new GBS infections (and no deaths) in pregnant women each year. It is also assumed that there are approximately 11,000 new GBS infections and 2,300 deaths in nonpregnant adults. The highest incidence of disease in nonpregnant adults is in people 65 years of age and older. See Table A25–1.

Disease Scenarios

For the purposes of the calculations in this report, the committee assumed that 90% of GBS disease in neonates is early-onset disease and 20% is late-onset disease. Disease associated with neonatal GBS infections includes bacteremia (86%) and meningitis (14%). Approximately 72% of neonatal GBS infections are early-onset bacteremia, 14% are late-onset bacteremia, 8% are early-onset meningitis, and 6% are late-onset meningitis.

For the purposes of the calculations in the report, the committee assumed that all pregnant women infected with GBS experience chorioamnionitis, endometritis, or bacteremia. These infections are assumed to be associated with 7 days at an HUI of .68. It was assumed that all nonpregnant adults infected

Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×

Table A25–1 Incidence of Group B Streptococcus Infection in Noninfants and Nonpregnant Women

Age Groups

Population

Incidence Rates (per 100,000)

Cases

<1

3,963,000

0.00

0

1–4

16,219,000

0.92

149

5–14

38,056,000

0.91

347

15–24

36,263,000

1.70

616

25–34

41,670,000

1.76

731

35–44

42,149,000

1.68

708

45–54

30,224,000

4.84

1,464

55–64

21,241,000

8.31

1,766

65–74

18,964,000

11.57

2,194

75–84

11,088,000

22.69

2,516

85+

3,598,000

22.70

817

Total

263,435,000

4.29

11,308

with GBS experience invasive disease (e.g., bacteremia, sepsis, soft tissue infections) associated with 19 days at an HUI of .66. See Table A25–2.

COST INCURRED BY DISEASE

Table A25–3 summarizes the health care costs incurred by GBS infections. For the purposes of the calculations in this report, it was assumed that GBS infections in pregnant women are associated with additional hospitalization at the time of delivery and associated inpatient and outpatient physician visits and medication. Costs are also included for screening for GBS and chemoprophylaxis of pregnant women. It was estimated that all nonpregnant adults with invasive GBS disease require hospitalization (including inpatient physician visits) and outpatient services as well.

For the calculation in this report, it was assumed that all infants with GBS require hospitalization, including multiple inpatient physician visits and diagnostics. It was assumed that a small percentage of infants with GBS meningitis will require long-term care for 10 years until death.

VACCINE DEVELOPMENT

The committee assumed that it will take 7 years until licensure of a GBS vaccine and that $300 million needs to be invested for approval for use in nonpregnant people, and an additional $100 million needs to be invested for that same vaccine to be used in pregnant women. Special considerations regarding

Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×

Table 25–2 Disease Scenarios for Group B Streptococcus Infection in Infants and Adults

 

% of Cases

Committee HUI Values

Duration (years)

INFANTS

 

Bacteremia—NICU

36.0%

0.24

0.027 (10 days)

Bacteremia—Non-NICU

36.0%

0.24

0.027 (10 days)

Meningitis

6.4%

0.27

0.047 (17 days)

Meningitis with impairment

1.1%

 

acute care (50% NICU; 50% Level 2)

 

0.27

0.047 (17 days)

permanent impairment—normal lifespan

 

0.53

26.804 (discounted quality adjusted life expectancy at birth)

Meningitis with early death

0.5%

 

acute care

 

0.27

0.047 (17 days)

permanent impairment

 

0.53

10.000 (10 years)

death by age 10

 

0.00

25.690 (discounted quality adjusted life expectancy at age 10)

LATE ONSET DISEASE—20% of infant cases

Bacteremia

14.0%

0.69

0.027 (10 days)

Meningitis

4.8%

0.27

0.047 (17 days)

Meningitis with impairment

0.8%

 

acute care

 

0.27

0.047 (17 days)

permanent impairment—normal lifespan

 

0.53

26.804 (discounted quality adjusted life expectancy at birth)

Meningitis with early death

0.4%

 

acute care

 

0.27

0.047 (17 days)

permanent impairment

 

0.53

10.000 (10 years)

death by age 10

 

0.00

25.690 (discounted quality adjusted life expectancy at age 10)

ADULTS

 

Maternal Infection

100%

 

inpatient

 

0.68

0.0192 (7 days)

outpatient treatment

 

0.0137 (5 days)

NONPREGNANT ADULTS

 

Invasive disease

100.0%

 

soft tissue, bone infection; bacteremia; urosepsis; pneumonia

 

0.66

0.052 (19 days)

Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×

Table 25–3 Health Care Costs Associated with GBS Disease in Infants and Adults

 

% with Care

Cost per Unit

Units per Case

Form of Treatment

INFANTS

 

EARLY ONSET DISEASE—80% of infant cases

Bacteremia—NICU

 

bacteremia, sepsis, pneumonia

100%

$12,000

1.0

hospitalization NICU

 

100%

$150

10.0

physician c

100%

$500

1.0

diagnostic c

Bacteremia—Level 2 care

 

bacteremia, sepsis, pneumonia

100%

$7,000

1.0

hospitalization non-NICU

 

100%

$150

10.0

physician c

100%

$500

1.0

diagnostic c

Meningitis

 

acute care

50%

$12,000

1.0

hospitalization NICU

 

50%

$7,000

1.0

hospitalization

100%

$150

17.0

physician c

100%

$500

1.0

diagnostic c

Meningitis with impairment

 

acute care

50%

$12,000

1.0

hospitalization NICU

 

50%

$7,000

1.0

hospitalization

100%

$150

17.0

physician c

100%

$500

1.0

diagnostic c

permanent impair-ment normal lifespan*

100%

$225

365.0

long-term care*/per year

Meningitis with early death

 

acute care

50%

$12,000

1.0

hospitalization NICU

 

50%

$7,000

1.0

hospitalization

100%

$150

17.0

physician c

100%

$500

1.0

diagnostic c

permanent impair-ment for 10-year period**

100%

$225

365.0

long-term care*/per year

LATE ONSET DISEASE—20% of infant cases

Bacteremia

 

bacteremia, sepsis, pneumonia

100%

$7,000

1.0

hospitalization

 

100%

$150

10.0

physician c

100%

$500

1.0

diagnostic c

Meningitis

 

acute care

50%

$12,000

1.0

hospitalization NICU

 

50%

$7,000

1.0

hospitalization

100%

$150

17.0

physician c

100%

$500

1.0

diagnostic c

Meningitis with impairment

 

acute care

50%

$1,200

1.0

hospitalization NICU

 

50%

$7,000

1.0

hospitalization

100%

$150

10.0

physician c

Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×

 

% with Care

Cost per Unit

Units per Case

Form of Treatment

 

100%

$500

1.0

diagnostic c

permanent impairment normal lifespan*

100%

$225

365.0

long-term care*/per year

Meningitis with early death

 

acute care

50%

$12,000

1.0

hospitalization NICU

 

50%

$7,000

1.0

hospitalization NICU

50%

$150

10.0

physician c

50%

$500

1.0

diagnostic c

permanent impairment for 10-year period**

100%

$225

365.0

long-term care*/per year

PREGNANT WOMEN

 

Maternal Infection (chorioamnionitis, endometritis, bacteremia)

additional inpatient treatment at time of delivery

100%

$1,000

1.0

hospitalization (in addition to normal delivery)

 

100%

$150

1.0

physician c

100%

$50

1.0

medication b

outpatient treatment

100%

$100

1.0

physician b

screening

90%

$50

1.0

diagnostic a

intrapartum chemoprophylaxis

25%

$50

1.0

medication b

NONPREGNANT ADULTS

 

Invasive disease

 

soft tissue, bone infection bacteremia; urosepsis; pneumonia

100%

$4,000

1.0

hospitalization

 

100%

$150

19.0

physician c

100%

$500

1.0

diagnostic c

outpatient

100%

$100

2.0

physician b

NOTE: *long-term care—$225/day is maintenance expenditure per resident for residential facilities for persons with mental retardation.

**cost per case is calculated as “present value” of annual cost for remaining life time (life expectancy at birth or 10 years, depending on scenario); additional discounting for immunization interval

development of a vaccine for use in pregnant women is discussed within the body of the report. Table 4–1 summarizes vaccine development assumptions for all vaccines considered in this report.

Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×

VACCINE PROGRAM CONSIDERATIONS

Target Population

The results of two vaccine strategies will be described. Both strategies involve annual immunization of 2,600,000 high-risk, nonpregnant adults (65 years of age or with specific chronic diseases). Both strategies involve immunization of younger females. One strategy involves annual immunization of pregnant women (approximately 1,630 primiparas). The other strategy involves annual immunization of 1,840,000 12-year-old girls. For the purposes of the calculations in this report, it is assumed that 30% of high-risk adults, 50% of 12-year-old girls, will utilize the vaccine. Additionally, it was assumed that utilization of the vaccine by pregnant women will either be 10% or 90%.

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

Immunization of Pregnant Women and At-Risk Adults

If a vaccine program for group B streptococci 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 37,400. 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 10,200 for 90% utilization by pregnant women and 4,500 for 10% utilization by pregnant women.

If a vaccine program for group B streptococci 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 $630 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 $310 million for 90% utilization by pregnant women and $45 million for 10% utilization by pregnant women.

If a vaccine program for group B streptococci were implemented today and the vaccine was 100% efficacious and utilized by 100% of the target population,

Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×

the annualized present value of the program cost would be $760 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 $285 million for 90% utilization by pregnant women and $120 million for 10% utilization by pregnant women.

Using committee assumptions of time and costs until licensure, the fixed cost of vaccine development has been amortized and is $12 million for a group B streptococci 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 $3,400. 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 -$1,500 for 90% utilization by pregnant women and $20,000 for 10% utilization by pregnant women. A negative value represents a saving in costs in addition to a saving in QALYs.

See Chapters 4 and 5 for details on the methods and assumptions used by the committee for the results reported.

Immunization of Girls at Puberty and At-Risk Adults

If a vaccine program for group B streptococci 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 33,000. 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 6,200.

If a vaccine program for group B streptococci 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 $435 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 $125 million.

If a vaccine program for group B streptococci 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 $800 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 $215 million.

Using committee assumptions of time and costs until licensure, the fixed cost of vaccine development has been amortized and is $9 million for a group B streptococci vaccine.

Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×

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 $11,000. 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 $16,000.

See Chapters 4 and 5 for details on the methods and assumptions used by the committee for the results reported.

READING LIST

Anthony BF. Group B Streptococcal Infections. In: Textbook of Pediatric Infectious Diseases. RD Feigin and JD Cherry eds. Philadelphia, PA: WB Saunder Company, 1992, pp. 1305–1316.


Blumberg HM, Stephens DS, Modansky M, et al. Invasive Group B Streptococcal Disease: The Emergence of Serotype V. Journal of Infectious Diseases 1996; 173:365–73.


CDC. Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP). Morbidity and Mortality Weekly Report 1996; 45:1–24.

CDC. Prevention of perinatal group B Streptococcal disease: a public health perspective. Morbidity and Mortality Weekly Report 1996; 45:1–24.


Edwards MS, Baker CJ. Streptococcus Agalactiae (Group B Streptococcus). In: Principles and Practice of Infectious Diseases. GL Mandell, JE Bennett, Dolin R eds. New York, NY: Churchill Livingstone, 1995, pp. 1835–1845.


Farley MM. A Population-Based Assessment of Invasive Disease Due to Group B Streptococcus in Nonpregnant Adults. The New England Journal of Medicine 1993; 328:1807–1811.

Farley MM. Group B Streptococcal Infection in Older Patients. Drugs & Aging 1995; 6:293–300.


Jackson LA, Hilsdon R, Farley MM, et al. Risk Factors for Group B Streptococcal Disease in Adults. Annals of Internal Medicine 1995; 123:415–420.


U.S. Bureau of the Census. Statistical Abstract of the U.S.: 1995 (115th edition). Washington, DC, 1995.


Ventura SJ, Martin JA, Mathews TJ, et al. Advance Report of Final Natality Statistics, 1994. Monthly Vital Statistics Report 1996; 44.

Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
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Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×
Page 306
Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×
Page 307
Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×
Page 308
Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×
Page 309
Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×
Page 310
Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×
Page 311
Suggested Citation:"Appendix 25: Streptococcus, Group B." Institute of Medicine. 2000. Vaccines for the 21st Century: A Tool for Decisionmaking. Washington, DC: The National Academies Press. doi: 10.17226/5501.
×
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Vaccines have made it possible to eradicate the scourge of smallpox, promise the same for polio, and have profoundly reduced the threat posed by other diseases such as whooping cough, measles, and meningitis.

What is next? There are many pathogens, autoimmune diseases, and cancers that may be promising targets for vaccine research and development.

This volume provides an analytic framework and quantitative model for evaluating disease conditions that can be applied by those setting priorities for vaccine development over the coming decades. The committee describes an approach for comparing potential new vaccines based on their impact on morbidity and mortality and on the costs of both health care and vaccine development. The book examines:

  • Lessons to be learned from the polio experience.
  • Scientific advances that set the stage for new vaccines.
  • Factors that affect how vaccines are used in the population.
  • Value judgments and ethical questions raised by comparison of health needs and benefits.

The committee provides a way to compare different forms of illness and set vaccine priorities without assigning a monetary value to lives. Their recommendations will be important to anyone involved in science policy and public health planning: policymakers, regulators, health care providers, vaccine manufacturers, and researchers.

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