Table 1 Parameter values used in the decision tree model and sensitivity analysis
Parameter | Base case estimate | Sensitivity range | References |
|---|---|---|---|
Epidemiologic | |||
Camp size [2015] | |||
Djibouti [destination from Somalia] | 22,080 | NA | [10] |
Algeria [destination from Sahara] | 90,000 | NA | [12] |
Mauritania [destination from Mali] | 48,000 | NA | [11] |
Crude Birth Rate (births per 1000 per year) [2015] | |||
Somalia [country of origin] | 44 | NA | [20] |
Western Sahara [region of origin] | 20 | NA | [20] |
Mali [country of origin] | 44 | NA | [20] |
Camp-based Birth cohort per year (Camp size x Crude Birth Rate) | |||
Djibouti | 972 | NA | |
Algeria | 1800 | NA | |
Mauritania | 2112 | NA | |
Average life expectancy [2015] | |||
Somalia [country of origin] | 56 | NA | [29] |
Morocco [nearest to Western Sahara] | 74 | NA | [29] |
Mali [country of origin] | 58 | NA | [29] |
Population proportion who are HBsAg+ | |||
Somalia | 0.1477 | 0.1377–0.1584 (95% CI) | [52] |
Morocco [substituted for Western Sahara] | 0.0109 | 0.0105–0.0114 (95% CI) | [52] |
Mali | 0.1307 | 0.1269–0.1347 (95% CI) | [52] |
Transmission rate | |||
Perinatal transmission in chronic infected mother | 0.91 | NA | [24] |
Disease progression, % | |||
HBV carrier to chronic infection | 0.073 | 0.003–0.073* | [25] |
Chronic hepatitis B to HBV carrier | 0.17 | 0.105–0.306 (Assumed max) | [25] |
Chronic hepatitis B to compensated cirrhosis | 0.129 | 0.004–0.153 | [53] |
Chronic hepatitis B to hepatocellular carcinoma (HCC) | 0.005 | 0.002–0.007 | [25] |
Compensated cirrhosis to decompensated cirrhosis | 0.054 | 0.028–0.1 | [25] |
Compensated cirrhosis to HCC | 0.03 | 0.01–0.1 | [27] |
Mortality rate | |||
Background mortality | Country-specific tables | [28] | |
Compensated cirrhosis | 0.037 | 0.03–0.044 | [53] |
Decompensated cirrhosis | 1 | 0.9–1 (Assumed, − 10%) | Assumed |
HCC | 1 | 0.9–1 (Assumed, − 10%) | [53] |
Clinical interventions | |||
Vaccine coverage (Hepatitis B, 3 doses) [2015] | |||
Djibouti | 0.78 | 0.63–1 (− 25% to 1)* | [15] |
Algeria | 0.95 | 0.73–1 (− 25% to 1)* | [15] |
Mauritania | 0.73 | 0.55–1 (− 25% to 1)* | [15] |
Vaccine protection, % | |||
Birth dose + Routine Immunization (RI) | 0.953 | 0.946–0.960 (95% CI) | [30] |
RI | 0.722 | 0.676–.765 (95% CI) | [30] |
Residual Susceptibility in Immunologic Failure | 0.05 | 0.0375–0.0625 (+/− 25%) | [34] |
Economic [2015 USD] | |||
UNICEF price per dose | 0.173 | NA | [54] |
Operational costs per dose or test | 0.93 | 0.11–2.00* (Assumed max) | |
Cost per rapid diagnostic test (RDT) | 0.50 | NA | [55] |
Sensitivity of RDT (pooled) | 0.948 | 0.946–0.960 | [32] |
Specificity of RDT (pooled) | 0.995 | 0.993–1 | [32] |