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APPENDIX 18
Neisseria meningitidis B

DISEASE BURDEN

Epidemiology

For the purposes of the calculations in this report, the committee estimated that there are 1,200 new cases of Neisseria meningitidis B (NMB) infection each year in the United States. Approximately half of these occur in children and infants under 5 years of age. Overall mortality rate was estimated at 0.05 per 100,000, or just under 150 deaths per year in the United States. Table A18–1 illustrates the age distribution of new annual NMB infections.

Disease Scenarios

For the purposes of the calculations in this report, the committee estimated that 65% of new cases of NMB manifest as meningitis. The acute manifestations of meningitis require hospitalization (most often in the intensive care unit or ICU). The committee-estimated health utility index (HUI) associated with those states ranges from 0.24 to 0.39 for those requiring ICU and non-ICU hospitalization, respectively.

Just fewer than 10% of patients with NMB meningitis have acute complications, such as gangrene, arthritis, and cardiac involvement. These complications were associated with a HUI of 0.27. Approximately 3.25% of patients experi-

See Appendix 28 for more information.



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Vaccines for the 21st Century: A Tool for Decisionmaking APPENDIX 18 Neisseria meningitidis B DISEASE BURDEN Epidemiology For the purposes of the calculations in this report, the committee estimated that there are 1,200 new cases of Neisseria meningitidis B (NMB) infection each year in the United States. Approximately half of these occur in children and infants under 5 years of age. Overall mortality rate was estimated at 0.05 per 100,000, or just under 150 deaths per year in the United States. Table A18–1 illustrates the age distribution of new annual NMB infections. Disease Scenarios For the purposes of the calculations in this report, the committee estimated that 65% of new cases of NMB manifest as meningitis. The acute manifestations of meningitis require hospitalization (most often in the intensive care unit or ICU). The committee-estimated health utility index (HUI) associated with those states ranges from 0.24 to 0.39 for those requiring ICU and non-ICU hospitalization, respectively. Just fewer than 10% of patients with NMB meningitis have acute complications, such as gangrene, arthritis, and cardiac involvement. These complications were associated with a HUI of 0.27. Approximately 3.25% of patients experi- See Appendix 28 for more information.

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Vaccines for the 21st Century: A Tool for Decisionmaking Table A18–1 Incidence and Mortality Rates for Neisseria meningitidis B Epidemiology Age Groups Population Incidence Rates (per 100,000) % Distribution of Cases <1 3,963,000 8.78 0.2900 1–4 16,219,000 1.48 0.2000 5–14 38,056,000 0.33 0.1057 15–24 36,263,000 0.33 0.1007 25–34 41,670,000 0.27 0.0927 35–44 42,149,000 0.20 0.0704 45–54 30,224,000 0.20 0.0505 55–64 21,241,000 0.20 0.0355 65–74 18,964,000 0.20 0.0317 75–84 11,088,000 0.20 0.0185 85+ 3,598,000 0.20 0.0060 Total 263,435,000 0.46 1.0017   Total cases 1,200 Age Groups Population Mortality Rates (per 100,000) % Distribution of Cases <1 3,963,000 1.05 0.2900 1–4 16,219,000 0.18 0.2000 5–14 38,056,000 0.04 0.1057 15–24 36,263,000 0.04 0.1007 25–34 41,670,000 0.03 0.0927 35–44 42,149,000 0.02 0.0704 45–54 30,224,000 0.02 0.0505 55–64 21,241,000 0.02 0.0355 65–74 18,964,000 0.02 0.0317 75–84 11,088,000 0.02 0.0185 85+ 3,598,000 0.02 0.0060 Total 263,435,000 0.05 1.0017   Total deaths 144 ence neurologic sequelae lasting a lifetime. These sequelae were estimated to be associated with an HUI of 0.6. The committee estimated that 35% of new cases of NMB manifest as bacteremia and sepsis. Approximately half of these cases require ICU hospitalization, such as those with Waterhouse Friederichsen syndrome. The HUI associated with bacteremia range from 0.16 to 0.71. Approximately 5.25% of patients experience complications and just over 1% experiences sequelae, such as amputation, that last a lifetime. Table A18–2 illustrates the estimated number of cases in each health state, the duration of time that state is experienced, and the HUI associated with each state.

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Vaccines for the 21st Century: A Tool for Decisionmaking Table A18–2 Disease Scenarios for Neisseria meningitidis B Infection   No. of Cases % of Cases Committee HUI Values Duration (years) MENINGITIS 780 65.00%   Meningitis (ICU) 624 52.00%   ICU   0.24 0.0055 (2 days) inpatient after ICU   0.28 0.0137 (5 days) Meningitis (no ICU) 156 13.00%   inpatient   0.39 0.0137 (5 days) Meningitis—complications 117 9.75%   acute complications (gangrene, arthritis, heart failure, etc.)   0.27 0.0274 (10 days) Meningitis—sequelae 39 3.25%   neurologic sequelae (cranial nerve damage, deafness, etc.)   0.60 23.2209 (discounted quality adjusted life expectancy at average age at onset) (average age at onset=18.3) BACTEREMIA/SEPSIS 420 35.00%   Bacteremia/Sepsis 210 17.50%   ICU (Waterhouse Friederichsen)   0.16 0.0110 (4 days) inpatient after ICU   0.44 0.0274 (10 days) Bacteremia/Sepsis (hospitalization; no ICU) 210 17.50% 0.71 0.0137 (5 days) Bacteremia/Sepsis—complications 63 5.25% 0.59 0.0274 (10 days) acute complications (cardiac, DIC, pneumonia, etc.)   Bacteremia/Sepsis—sequelae 13 1.05% 0.63 23.2209 (discounted quality adjusted life expectancy at age 18) (average age at onset) COST INCURRED BY DISEASE Table A18–3 summarizes the health care costs incurred by NMB infections. For the purposes of the calculations in this report, it was assumed that patients with meningitis incur costs associated with hospitalization (hospital costs, specialist physicians, diagnostics). Patients who experience complications incur additional hospitalization costs. The small percentage of patients who

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Vaccines for the 21st Century: A Tool for Decisionmaking Table A18–3 Health Care Costs Associated with Neisseria meningitidis B Infection   % with Care Cost per Unit Units per Case Form of Treatment Meningitis (ICU)   uncomplicated 100% $7,000 1.0 hospitalization   100% $150 3.0 physician b 100% $50 1.0 medication b 100% $100 1.0 diagnostic b 10% $500 1.0 diagnostic c Meningitis—complications   acute complications (gangrene, arthritis, heart failure, etc) 100% $7,000 1.0 hospitalization   100% $150 6.0 physician b 100% $50 1.0 medication b 100% $100 1.0 diagnostic b 100% $500 1.0 diagnostic c Meningitis—sequelae   neurologic sequelae (cranial nerve damage, deafness, etc) 100% $100 6.0 physician b (per year) Bacteremia/Sepsis   ICU (Waterhouse Friederichsen) 100% $4,000 1.0 hospitalization   100% $100 3.0 physician b Bacteremia/Sepsis (no ICU)   inpatient 100% $4,000 1.0 hospitalization   100% $100 3.0 physician b 100% $100 1.0 diagnostic b Bacteremia/Sepsis—complications   acute complications (cardiac, disseminated intravascular coagulation, pneumonia, etc.) 100% $4,000 1.0 hospitalization   100 % $100 3.0 physician b 100% $500 1.0 diagnostic c 20% $7,000 1.0 amputation 20% $500 2.0 surgical staff 20% $3,000 1.0 rehabilitation experience neurologic sequelae incur costs associated with multiple visits per year to a specialist and therapists for the duration of their life. Costs associated with NMB-related bacteremia and sepsis include hospitalization and related expenses (physicians, diagnostics). Those who experience complications incur additional costs associated with hospitalization and rehabilitation for the small number of patients who require amputation.

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Vaccines for the 21st Century: A Tool for Decisionmaking VACCINE DEVELOPMENT The committee assumed that the development of an NMB vaccine is feasible and that licensure can occur within the middle of the time frame within the charge. The estimates for the model are that it will take 7 years until licensure and that $300 million needs to be invested. Table 4–1 summarizes vaccine development assumptions for all vaccines considered in this report. VACCINE PROGRAM CONSIDERATIONS Target Population The committee’s model assumes that immunization with this vaccine will occur only during infancy. It is estimated that 90% of infants will receive the immunization. Vaccine Schedule, Efficacy, and Costs The committee estimated that this would be a relatively low-cost vaccine, costing $50 per dose. Vaccine administration would cost an additional $10. The committee has accepted default assumptions that this vaccine will require a series of 3 doses and that effectiveness will be 75%. Table 4–1 summarizes vaccine program assumptions for all vaccines considered in this report. RESULTS If a vaccine program for N. meningitidis B 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 2,300. 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 1,100. The mortality accounts for a large portion of the lost QALYs, due primarily to the deaths in children and infants. QALY loss associated with morbidity is largely due to the lifetime sequelae associated with both meningitis and bacteremia. If a vaccine program for N. meningitidis B 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 $6 million. Using committee assumptions of less-than-ideal efficacy and utilization and

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Vaccines for the 21st Century: A Tool for Decisionmaking including time and monetary costs until a vaccine program is implemented, the annualized present value of the health care costs saved would be $2.9 million. If a vaccine program for N. meningitidis B 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 $450 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 N. meningitidis B 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 $300,000. 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 $400,000. See Chapters 4 and 5 for details on the methods and assumptions used by the committee for the results reported. READING LIST Adams AG, Deaver KA, Cochi SL, et al. Decline of Childhood Haemophilus influenzae Type b (Hib) Disease in the Hib Vaccine Era. JAMA 1993; 269:221–226. Apicella MA. Neisseria Meningitidis. In: Principles and Practice of Infectious Diseases. GL Mandell, JE Bennett, Dolin R eds. New York, NY: Churchill Livingstone, 1995, pp. 1896–1908. Bushore M, Marante AA. Emergency Department Stabilization of Pediatric Patients with Bacterial Meningitis—Current Advances. Emergency Medical Clinics of North America; 9:239–250. Durand ML, Calderwood SB, Weber DJ, et al. Acute Bacterial Meningitis in Adults—A Review of 493 Episodes. The New England Journal of Medicine 1993; 328:21–28. Frasch CE. Meningococcal Vaccines: Past, Present and Future. In: Meningococcal Disease. K Cartwright ed. New York, NY: John Wiley & Sons Ltd., 1995, pp. 245–283. Glode MP, Smith AL. Meningococcal Disease. In: Textbook of Pediatric Infectious Diseases. RD Feigin and JD Cherry eds. Philadelphia, PA: WB Saunder Company, 1992, pp. 1185–1197. Jackson LA, Wenger JD. Laboratory-Based Surveillance for Meningococcal Disease in Selected Areas, United States, 1989–1991. Morbidity and Mortality Weekly Report 1993; 42:21–30. Milagres LG, Ramos SR, Sacchi CT, et al. Immune Response of Brazilian Children to a Neisseria meningitidis Serogroup B Outer Membrane Protein Vaccine: Comparison with Efficacy. Infection and Immunity 1994; 62:4419–4424.