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Table 1 Model input parameter values and ranges

From: Cost-effectiveness of Rotavirus vaccination in Vietnam

Epidemiological parameters

    

Parameters

Baseline estimates

Rangesa

Distributionsb

Sources

5-year cumulative numbers of rotavirus gastroenteritis death (for a 2004 birth cohort)

1,673

1,514–1,833c

Not varied

[38]

Estimated age-specific incidence rate of rotavirus diarrhea associated deaths (per 100,000 per month)d

  

Not varied

[37] Estimated

   age 0–1 month

0.0

Not varied

  

   age 2 months

3.5

2.8–4.2

  

   age 3–5 months

3.8

3.0–4.5

  

   age 6–8 months

6.5

5.2–7.8

  

   age 9–11 months

12.2

9.7–14.6

  

   age 12–14 months

15.3

12.2–18.3

  

   age 15–17 months

14.0

11.2–16.8

  

   age 18–23 months

7.9

6.3–9.5

  

   age 24–35 months

3.4

2.7–4.1

  

   age 36–47 months

2.9

2.3–3.5

  

   age 48–59 months

2.6

2.1–3.1

  

Cumulative probability of primary infection (by 2 months of age), %

3

0–8

Not varied

Estimated

Ratio of numbers of hospitalizations to deaths attributable to rotavirus gastroenteritis

20.7

10.35–31.05

Not varied

[13]

Ratio of numbers of outpatient visits to deaths attributable to rotavirus gastroenteritis

96.6

32.2–103.0

Not varied

Assumed

Ratios of annual incidence of different rotavirus infection outcomes (without vaccination)

    

   Primary infections

    

- mild vs. severe casese

4.3

2.15–6.45

Not varied

[8]

- asymptomatic vs. severe casese

4.1

2.05–6.15

Not varied

[8]

   Secondary infections

    

- mild vs. severe casese

21.5

10.8–32.3

Triangular

[8]

- asymptomatic vs. severe casese

19.0

9.5–28.5

Triangular

[8]

   Secondary vs. primary severe infections

0.167

0.125–0.209

Not varied

[8]

   Tertiary vs. primary 'any' infectionsf

0.478

0.239–0.717

Triangular

[8]

   Quaternary vs. primary 'any' infectionsf

0.372

0.186–0.558

Triangular

[8]

Vaccine characteristics

    

Vaccine coverage (2 doses)

94

90–98

Triangular

[13]

Serotype-specific vaccine efficacy (against severe gastroenteritis), %

  

Not varied

 

   G1P[8]

90.8

70.5–98.2c

 

[26]

   G3P[8], G4P[8], G9P[8]

86.9

62.8–96.6c

 

[26]

   G2P[4] and other combinations of G and P

45.4

0–85.6

 

[26]

Vaccine efficacy against severe gastroenteritis, % (adjusted for the serotype distribution)

77

43–99

Triangular

Estimated

Vaccine efficacy against mild gastroenteritis, % (not adjusted for the serotype distribution)

41

21–62

Triangular

Estimated

Costs g

    

   Vaccination costs

    

Vaccine price (per dose)

5

0.1–10

Triangular

Assumed

Vaccine wastage rate, %

10

0–20

Triangular

Assumed

Delivery costsh (per dose)

0.7

0.35–1.05

Triangular

Estimated

   Disease treatment costs

    

Outpatient visit (per episode)

3.49

2.88–4.11

Triangular

[13]

Hospitalization (per episode)

19.97

14.98–24.96

Triangular

[13]

   Direct nonmedical costs

    

Transport

    

- for outpatient visit

0.69

0.52–0.86

Triangular

[13]

- for hospitalization

4.46

3.35–5.58

Triangular

[13]

Caregiver's time

    

- for outpatient visit

2.82

2.12–3.53

Triangular

[13]

- for hospitalization

7.86

5.90–9.83

Triangular

[13]

Discount rate, %

3

0–6

Not applicable

Assumed

Disability weight for diarrhoeal episode

0.119

0.086–0.152

Triangular

[47]

  1. a This column shows the ranges of parameters that were varied during one-way sensitivity analyses.
  2. b This column shows parameters that were varied during the probabilistic sensitivity analysis and distributions assigned to them. Since data often did not contain enough information from which to estimate distribution parameters, triangular distributions were chosen for all parameters.
  3. c 95% confidence interval.
  4. d Monthly incidence rates were converted to weekly transition probabilities within the model, assuming an exponential relationship between the cumulative incidence at different time (age) intervals and time (age). For details, see Additional file 1, which provides a more detailed explanation of the steps taken.
  5. e 'Severe cases' means the aggregate number of outpatient visits, hospitalization, or disease-specific deaths attributable to rotavirus gastroenteritis.
  6. f 'Any' infection includes severe cases, mild cases, and asymptomatic cases.
  7. g All costs are expressed in 2004 US dollars.
  8. h Delivery cost is defined as any costs incurred in distributing and administering vaccines (other than costs for vaccine purchase), including all capital costs (e.g., cold chains and vehicles) and shared operational costs (e.g., salary for personnel, transportation, maintenance, training, social mobilization, and surveillance).
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BMC Public Health

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