Table 2.
Variables and Sources
| Variable | Base Case (Range) | Source |
|---|---|---|
| Susceptible Population Parameters | ||
| Population | 8,300,000 | New York Vital Statistics (7) |
| Age (range, years) | 0-100 | New York Vital Statistics (7) |
| Percent female | 53 | New York Vital Statistics (7) |
| Pre-existing population immunity | 0% (0-10%) | Assumed, WHO (8) |
| Infected Population Parameters | ||
| R0 | 1.8 (1.4-2.2) | Assumed, CDC Severity Index 5 (9) |
| Non-pharmaceutical interventions reduction in contacts | 25% (10-70%) | Assumed, Cowling et al. (10) |
| Number of infected individuals at start of pandemic | 1,000 (100-10,000) | Assumed |
| Probability of symptomatic infection | 67% (50-90%) | Ferguson et al. (11), Longini et al. (12), Katz et al. (13), Dinh et al (14)., Vong et al. (15), Buxton Bridges et al. (16), Aparnthanarak et al (17)., Liem et al (18)., Wang et al.(19) |
| Reduced infectiousness by incubating | 50% (10-62.5%) | Hayden et a (20)., Wein et al. (21) |
| Reduced infectiousness by asymptomatic | 25% (10-50%) | Hayden et al (20)., Wein et al. (21) |
| Probability of isolating given symptomatic infection | 50% (37.5-62.5%) | Longini et al.(22) |
| Mean incubation time (days) | 2 (1-9) | CDC seasonal influenza data (23), WHO influenza A (H5N1) data (8) |
| Mean duration of infectiousness (days) | 4 (3-10) | Hayden et al. (20), Leekha et al. (24) |
| Mean duration of symptomatic illness (days) | 10 (7.5-12.5) | CDC (23) |
| Proportion of symptomatic patients requiring inpatient care | 10% (7.5-12.5%) | CDC (25), HHS (9) |
| Mean duration of non-ICU inpatient stay (days) | 5 (3.75-6.25) | CDC (25), HHS (9) |
| Proportion of inpatients admitted to Influenza Care Center | 90% (0-95%) | Assumed, NYC Department of Mental Health and Hygiene (26) |
| Proportion of inpatients admitted to hospital | 10% (5-100%) | Assumed, NYC Department of Mental Health and Hygiene (26) |
| Proportion of hospital patients requiring ICU care | 10% (7.5-12.5%) | CDC (25), HHS (9) |
| Mean duration of ICU stay (days) | 10 (7.5-12.5) | CDC (25), HHS (9) |
| Recovered Population Parameters | ||
| Susceptibility to re-infection following recovery | 5% (2-25%) | Smith et al. (27) Monto et al. (28) Sonoguchi et al (29). Davies et al.(30) |
| Timing of waning immunity (months) | 5 (2-8) | Smith et al. (27) Monto et al. (28) Sonoguchi et al (29). Davies et al. (30) |
| Mortality | ||
| Case-fatality proportion | 2.5% (0.5%-60%) | Seasonal flu clinical case-fatality (23), CDC Severity Index 5 Case Fatality (9), Current influenza A (H5N1) Case Fatality (8) |
| Mortality threshold for reactive social distancing | 10 per 10,000 (5-50 per 10,000) | Bootsma and Ferguson (31) |
| Reactive social distancing memory period | 30 days (1-40) | Bootsma and Ferguson (31) |
| Intervention Effectiveness | ||
| Zanamivir prophylaxis | 74% (63%-82%) | Khazeni et al. (32) |
| Oseltamivir prophylaxis | 37% (32-41%) | Khazeni et al. (32) |
| Non-adjuvanted one-dose vaccine | 20% (10-80%) | Assumed |
| Non-adjuvanted two-dose vaccine | 30% (10-80%) | Assumed |
| Adjuvanted one-dose vaccine | 40% (10-80%) | Assumed |
| Adjuvanted two-dose vaccine | 50% (10-80%) | Assumed |
| Intervention side effects | ||
| Neuraminidase Inhibitor | ||
| Mild-moderate side effects | 10% (5-20%) | Tamiflu and Relenza Package Inserts (33, 34) |
| Severe side effects | 0.001% (0-0.01%) | Assumed, Khazeni et al. (32) |
| Risk of death from severe side effects | 5% (1-10%) | Assumed |
| Vaccination | ||
| Mild-moderate side-effects | 45% (5-75%) | Treanor et al. (35), Leroux-Roels et al. (36) |
| Severe side effects for non-adjuvanted vaccine | 0.001% (0-0.01%) | Neustadt and Fineberg (37) |
| Severe side effects for adjuvanted vaccine | 0.001% (0-0.01%) | Neustadt and Fineberg (37) |
| Risk of death from severe side effects | 5% (1-10%) | Chio et al. (38) |
| Risk of long-term care from severe side effects | 5% (1-10%) | Kissel et al. (39) |
| Intervention side effects reduction in quality of life* | ||
| Neuraminidase Inhibitor | ||
| Mild-moderate side effects | 0.05 (0-0.1) | Assumed, Tamiflu and Relenza Package Inserts (33, 34) |
| Severe side effects | 0.5 (0-1) | Assumed, Tamiflu and Relenza Package Inserts (33, 34) |
| Duration of mild-moderate side effects (days) | 40 (10-100) | Assumed, Tamiflu and Relenza Package Inserts (33, 34) |
| Duration of hospitalization for severe side effects (days) | 14 (7-28) | Assumed |
| Vaccination | ||
| Mild-moderate side-effects | 0.05 (0-0.1) | Assumed, Treanor et al. (35), Leroux-Roels et al. (36), CDC(40) |
| Severe side effects | 0.5 (0-1) | Assumed, Neustadt and Fineberg (37) |
| Duration of mild-moderate side effects (days) | 2 (1-7) | Treanor et al. (35), Leroux-Roels et al. (36), CDC(40) |
| Duration of hospitalization for severe side effects (days) | 14 (7-28) | Chio et al. (38) |
| Influenza-related quality of life | ||
| Uninfected/Asymptomatic | 0.96 (0.92-1.00) | New York Census (7), Beaver Dam Health Outcomes (41) |
| Symptomatic Influenza | 0.8 (0.7-0.9) | Turner et al. (42) |
| Post-influenza disabled state for patients requiring ICU care | 0.9 (0.85-0.95) | Assumed |
| Costs | ||
| Vaccine | ||
| Antigen per μg ($) | 0.45 (0.33-0.55) | HHS (43) |
| Adjuvant ($) | 7.00 (5.25-8.75) | BARDA (personal communication – Michael Perdue) |
| μg adjuvant per vaccine | 3.8 (1.9-90) | HHS (44) |
| Stockpiling (annual, $) | 1.00 (0.01-2.00) | Assumed, Sangrujee et al. (45) |
| Administration | ||
| Antigen | 8.73 (6.54-10.91) | Calculated: 10 minutes of nurse wages (46) |
| Adjuvant | 8.73 (6.54-10.91) | Calculated: 10 additional minutes of nurse wages for mixing (46) |
| Patient Time | 10.55 (5.28-21.10) | U.S. Bureau of Labor Statistics (47) |
| Antiviral (per 40-day prophylactic course, $) | ||
| Oseltamivir | 165.78 (48.00-331.56) | Veterans Affairs (personal communication – Mark Hlodniy) |
| Zanamivir | 91.08 (48.00-182.16) | HHS (48) |
| Proportion oseltamivir vs. zanamivir | 50% (0-100%) | Assumed |
| Stockpiling (annual, $) | 0.23 (0.01-1.00) | Sangrujee et al.(45) |
| Dispensing | 10.49 (7.86-13.11) | Bravata et al. (49) |
| Rotation of stockpile (years) | ||
| Antigen | 2 (1-10) | HHS (44) |
| Adjuvant | 3 (1-10) | BARDA (personal communication – Michael Perdue) |
| Antivirals | 5 (1-10) | Tamiflu and Relenza expirations (33, 34) |
| Daily health care costs ($) | ||
| Patient with severe side effects (treated in ICU) | 3,739.05 (2,804.29 – 4,673.82) | Desta et al. (50) |
| General medical hospitalized patient | 1,830.46 (1429.37-1870.54) | Talbird et al. (51) |
| ICU hospitalized patient | 3,739.05 (2,804.29 – 4,673.82) | Desta et al. (50) |
| Long-term treatment facility costs | 313.05 (234.79-391.31) | Metlife Survey (52) |
| Influenza Care Center patient | 100.00 (75.00-1659.00) | Santa Clara County Public Health Department (personal communication – Sara Cody) |
| Normal health care expenditures | 19.56 (14.67-24.45) | Statistical Abstract of the United States(53) |
| Other variables | ||
| Discount Rate (annual %) | 3 (0-5%) | Weinstein et al.(54) |
*
Quality of life variables represent a person's preference for a given state of health and are scaled form 0 to 1, with 1 equivalent to perfect health.