Background
Methods
Modeling approach
Vaccination strategies
Model parameters and data sources
Parameter | Base Case | Range | Distribution | Reference |
---|---|---|---|---|
Demography | ||||
Population 2014 | 8,117,564 | Fixed | [10] | |
Age Specific All-cause Mortality | Varies | Fixed | [8] | |
Infection | ||||
Force of Infection | Fixed | |||
Scale parameter | 0.854327 | Fixed | ||
Shape parameter | 0.00159689 | Fixed | ||
Shape parameter | 11.5766 | Fixed | ||
Duration of Maternal Immunity (mo) | 6.5 | Fixed | [45] | |
Latency period (d) | 14 | Fixed | ||
Age-specific mean duration of infectiousness (wk) | Fixed | |||
0–4 y | 3.5 | |||
5–9 y | 3.0 | |||
10+ y | 2.5 | |||
Vaccine | ||||
Vaccine efficacy, one does only (%) | 100 | 87.3–100 | Derived Distribution | [22] |
Vaccine efficacy, two doses (%) | 100 | 87.3–100 | Derived Distribution | Assumed |
Median duration of vaccine-derived immunity, one dose only (y) | 21 | 20.3–21.9 | Gamma (2647.1, 0.0079) | Assumed |
Median duration of vaccine-derived immunity, two doses (y) | 32 | 30.9–33.4 | Gamma (2517.63,0.127) | [23] |
Vaccination Strategy | ||||
Vaccine uptake, universal strategy, first dose (%) | 95% | 80–97 | Beta (34.37426,1.0007488) | Assumed |
Vaccine adherence, probability of second dose given first dose (%) | 95% | 70–95 | Beta (27.15759,2.49654) | Assumed |
Clinical Outcomes | ||||
Under reporting factor | 11.76 | Fixed | Estimated | |
Probability an infection is icteric | Varies | Fixed | [20] | |
Proportion of icteric infections hospitalized (%) | [21] | |||
≤ 4 y | 0.395 | Dirichlet(D1)a | ||
5–14 y | 1.45 | Dirichlet(D2) | ||
15–39 y | 1.91 | Dirichlet(D3) | ||
40–59 y | 1.57 | Dirichlet(D4) | ||
60+ y | 1.7 | Dirichlet(D5) | ||
Probability of fulminant hepatitis A from an icteric infection (%) | [21] | |||
≤ 4 y | 0.0323 | Dirichlet(D1) | ||
5–14 y | 0.00425 | Dirichlet(D2) | ||
15–39 y | 0.0578 | Dirichlet(D3) | ||
40–59 y | 0.468 | Dirichlet(D4) | ||
60+ y | 0.68 | Dirichlet(D5) | ||
Probability of liver transplant from an icteric infection (%) | [21] | |||
≤ 4 y | 0.00606 | Dirichlet(D1) | ||
5–14 y | 0.000797 | Dirichlet(D2) | ||
15–39 y | 0.0108 | Dirichlet(D3) | ||
40–59 y | 0.0877 | Dirichlet(D4) | ||
60+ y | 0.017 | Dirichlet(D5) | ||
Probability of death from an icteric infection (%) | [21] | |||
≤ 4 y | 0.00468 | Dirichlet(D1) | ||
5–14 y | 0.000616 | Dirichlet(D2) | ||
15–39 y | 0.00838 | Dirichlet(D3) | ||
40–59 y | 0.0678 | Dirichlet(D4) | ||
60+ y | 0.456 | Dirichlet(D5) | ||
Probability of death during first year of liver transplant (%) | 11.6 | 6.0–42.0 | Beta (1.14982, 8.76245) | [50] |
Probability of death from year 2 and beyond after liver transplant (%) | 4.4 | 2.4–11.0 | Beta (3.80137, 82.5935) | [50] |
Duration of outpatient icteric infection (d) | 34.4 | 17–40 | Gamma (34.37,1.00) | [51] |
Duration of inpatient icteric infection (d) | 67.8 | 27–78 | Gamma (27.16,2.50) | [51] |
Economic Parameters | ||||
Cost of one-dose vaccine (2015 $) | 10.00 | 8.00–14.00 | Gamma (42.6844, 0.234277,1.1,3) | Estimated |
Test Costs | 22.55 | Fixed | [26] | |
Cost of one-dose administration | 1.91 | Fixed | Estimated | |
outpatient cost | $15.06 | 10–25 | Gamma (8.71228, 7.77408) | [27] |
outpatient visits | 3 | 1–4 | Estimated | |
hospitalization cost | $ 111.5 | 80–150 | Gamma (6.43896, 81.4262) | [26] |
hospitalization duration | 4.5 | 3–7 | Estimated | |
fulminant cost | $35,715 | 32,143–39,278 | Gamma (385.022, 92.7609) | [26] |
annual cost of patients with liver transplant (1st year) | $70,000 | 50,000–90,000 | Gamma (47.0596, 1487.48) | [26] |
annual cost of patients with liver transplant (subsequent years) | 43,203 | 34,563–51,843 | Gamma(96.0533, 449.781) | Estimated |
Public health cost of a reported infection (2013 $) | 0 | 0–15 | Gamma(1.092722,3.660584) | Estimated |
work loss, outpatient (d) | 15.5 | 7–18 | Gamma(30.51056,0.508021) | [51] |
work loss, inpatient (d) | 33.2 | 10–25 | Gamma(75.2776,0.4410342) | [51] |
work loss, fulminant (d) | 33.2 | 10–25 | Gamma(75.2776,0.4410342) | [51] |
work loss, year of transplant (d) | [25] | |||
0–17 y | 153.2 | 145–160 | Gamma(1602.9, 0.0955766) | |
18–40 y | 245 | 238–253 | Gamma (4099.41, 0.0597646) | |
41–55 y | 271 | 268–274 | Gamma (31,347.9, 0.00864492) | |
56–62 y | 288 | 284–291 | Gamma (26,011.2, 0.0110721) | |
63+ | 314 | 306–321 | Gamma (6733.62, 0.0466316) | |
Labor force participation (%) | [52] | |||
16–19 y | 3.15 | 1–28 | Beta[1.4452,44.4342] | |
20–24 y | 33.8 | 31–72 | Beta[6.57547,12.8786] | |
25–34 y | 64.0 | 57–70 | Beta[133.435,75.0572] | |
35–44 y | 59.6 | 51 – 71 | Beta[54.5338,36.9658] | |
45–54 y | 47.1 | 35–59 | Beta[30.8364,34.6337] | |
55–64 y | 30.7 | 0–62 | Beta[2.30395,5.20078] | |
65+ | 10.0 | 0–23 | Beta[2.51432,22.6289] | |
Median Monthly earnings (2014 $) | [53] | |||
< 25 y | 292 | 137–350 | Gamma(13.6337, 21.4175) | |
25+ | 365 | 250–650 | Gamma(28.8788, 10.1112) | |
Discount rate per year, % | 3 | 0–5 | Assumed | |
Utilities | ||||
Average population norms | [31] | |||
20–29 y | .920 | 0.913–0.927 | Beta(5307.7008, 461.5392) | |
30–39 y | .905 | 0.898–0.912 | Beta(6099.1932,640.2468) | |
40–49 y | .874 | 0.867–0.882 | Beta(6572.4195,947.5113) | |
50–59 y | .848 | 0.840–0.857 | Beta(5810.9376,1041.5832) | |
60–69 y | .824 | 0.812–0.836 | Beta(3187.1645,680.7536) | |
70–79 y | .785 | 0.771–0.798 | Beta(2791.9027,764.6613) | |
80+ y | .744 | 0.720–0.768 | Beta(944.3511,324.9380) | |
Persons with anicteric hepatitis A | .830 | 0.789–0.867 | Beta(291.9525,59.7975) | [21] |
Persons with icteric hepatitis A | .642 | 0.607–0.682 | Beta(410.1317,228.3050) | [29] |
Persons with liver transplant | .730 | 0.630–0.840 | Beta(49.4052,18.2732) | [30] |
Demographic parameters
Transmission rates and force of infection
Hepatitis a virus infection parameters
Vaccine parameters
Costs
Utilities
Implementation
Analyses
Base case and sensitivity analyses
Model transparency and validation
Results
Base case
Epidemiology results
Cumulative events avoided with vaccination | Universal Vaccination | |||
---|---|---|---|---|
5 years | 10 years | 25 years | 50 years | |
Any Infection | 326,900 | 748,608 | 1,618,125 | 4,260,589 |
Asymptomatic | 225,772 | 509,773 | 1,085,502 | 2,813,184 |
Symptomatic | 101,127 | 238,835 | 532,624 | 1,447,405 |
Outpatient | 99,572 | 235,120 | 524,228 | 1,424,252 |
Hospitalizations | 1522 | 3633 | 8195 | 22,475 |
Fulminant cases | 24 | 61 | 151 | 508 |
Liver Transplants | 5 | 11 | 28 | 95 |
Deaths | 4 | 9 | 22 | 76 |
Cost-effectiveness results
Cumulative outcomes | Universal Vaccination | |||
---|---|---|---|---|
5 y | 10 y | 25 y | 50 y | |
QALY’s Gaineda | 4800 | 10,521 | 24,144 | 37,502 |
Vaccination Cost (millions) | $9.40 | $17.52 | $35.76 | $52.83 |
Disease Cost Avoided (millions) | $8.06 | $18.60 | $47.78 | $81.41 |
Indirect cost avoided (millions) | $0.99 | $2.61 | $8.00 | $14.03 |
Total Cost Savings(millions, including indirect costs) | – | $3.69 | $20.03 | $42.60 |
Total Cost Savings(millions, excluding indirect cost) | – | $1.09 | $12.02 | $28.57 |
ICERb ($/QALY, including indirect costs) | 75 | Cost saving | Cost saving | Cost saving |
ICER ($/QALY, excluding indirect cost) | 281 | Cost saving | Cost saving | Cost saving |