TABLE 1

Summary of Input Parameters for the Model

VariableBase-Case ValueSource
Population and incidence
    No. of children in cohort
        Region 1942 913National Vital Statistics41 (2003)
        Region 2571 155National Vital Statistics41 (2003)
        Region 32 507 658National Vital Statistics41 (2003)
    Overall annual hepatitis A incidence per 100 000 in the absence of vaccination, 2005a
        Region 122.6Estimate based on Samandari et al9 (2004)
        Region 214.1Estimate based on Samandari et al9 (2004)
        Region 36.7Estimate based on Samandari et al9 (2004)
    Annual decline in incidence without vaccination, %1.4Samandari et al9 (2004)
Vaccination
    Probability of receiving first dose if recommended.93Calculated from CDC26 (2004)
    Probability of receiving second dose if recommended.87Calculated from CDC26 (2004)
Probability of receiving first dose under previous recommendations, by regionb
    Recommended.5Fiore et al11 (2005)
    Considered.25Fiore et al11 (2005)
    No recommendation.01Fiore et al11 (2005)
Antibody titer after vaccination with hepatitis A vaccine, mIU/mL
    After first dose141Van Herck et al30 (2000)
    After second dose1120Van Herck et al30 (2000)
Annual decline in antibody titer after vaccination, %
    Years 0–420Van Herck et al30 (2000)
    Years 5–955Unpublished data
Antibody titer threshold for immunity, mIU/mL20Delem et al42 (1993)
Outcomes of infection
    Probability of nonspecific symptoms given nonicteric infection.5Assumption
    Probability of icteric infection according to agec
    0–4 y.076Armstrong et al4 (2002)
    5–14 y.512Armstrong et al4 (2002)
    15–95 y.832Armstrong et al4 (2002)
    Probability of liver transplant given icteric infection
    Dependent on age.00002–.00241Schiodt et al17 (2003)
Probability of death given icteric infection
    0–4 y.00030CDC14 (2001)
    5–14 y.00004CDC14 (2001)
    15–39 y.00054CDC14 (2001)
    40–59 y.00436CDC14 (2001)
    60–95 y.01276CDC14 (2001)
    Probability that an icteric case is reportedc.23Armstrong et al4 (2002)
    Probability of hospitalization given that an icteric infection is reported according to age
    0–4 y.05CDC14 (2001)
    5–14 y.17CDC14 (2001)
    15–39 y.23CDC14 (2001)
    40–59 y.19CDC14 (2001)
    60–95 y.2CDC14 (2001)
Costs of medical intervention, $
    Average cost of childhood vaccine per dose17.96CDC27 (2006)
    Average cost of adult vaccine per dose55.49CDC27 (2006)
    Vaccine administration cost per dose according to age
        1 yd6CDC14 (2001), assumption
    Symptomatic anicteric infection requiring outpatient visit84.16American College of Physicians21
    Unreported outpatient icteric274Berge et al2 (2000), assumption
    Reported outpatient icteric821Berge et al2 (2000)
    Inpatient icteric8111Dalton et al19 (1996) and Berge et al2 (2000)
    Fulminant disease without transplant24 138Berge et al2 (2000)
    Liver transplant (first year)285 900Hauboldt et al20 (1999)
    Liver transplant (subsequent years)25 598Berge et al2 (2000)
    Public health cost per reported case667CDC Division of Viral Hepatitis
Quality-of-life values
    Quality-adjusted value of life during icteric hepatitis A0.41Jacobs et al24 (2002)
    Quality-adjusted value of life during anicteric hepatitis A with symptoms0.83Mittmann et al25 (2001)
    Duration of outpatient icteric hepatitis A, d34.4Berge et al2 (2000)
    Duration of inpatient icteric hepatitis A, d67.8Berge et al2 (2000)
    Duration of anicteric hepatitis A with symptoms, d3Assumption
  • Range and distributional assumptions can be found in the technical report (www.rti.org/pubs/hepa-model_report_rein.pdf).

  • a Relative risk of infection varies widely by age and region.

  • b Scenario 2 compares current immunization levels with increased levels under routine recommendations.

  • c Because the values of several other variables were a function of the probability of icteric infection and the probability that an icteric case is reported, these values were held constant in the simulations.

  • d Vaccine administration at age 1 year is assumed to be shared with ≥1 other vaccine administered at the same visit.