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Table 1 Assumptions on epidemiology, natural history, and disability weights

From: Economic evaluation of pneumococcal conjugate vaccination in The Gambia

Parameters Baseline estimates Rangesa Distributionsb Sources
Epidemiological parameters     
Incidence of primary endpoint pneumonia (per 1000/person-year)c     
   < 6 months 32 25-41d Not varied [9]
   6-11 months 49 42-56d Not varied [9]
   12-17 months 46 40-54d Not varied [9]
   18-23 months 42 36-50d Not varied [9]
   24-29 months 20 15-27d Not varied [9]
   30-59 months 5 3-7 Not varied [9]
Incidence of non-primary endpoint pneumonia (per 1000 person-year)c     
   < 6 months 165 144-190 Not varied [9]
   6-11 months 184 166-203 Not varied [9]
   12-17 months 255 229-278 Not varied [9]
   18-23 months 214 193-237 Not varied [9]
   24-29 months 155 135-181 Not varied [9]
   30-59 months 27 23-31 Not varied [9]
Estimated incidence of pneumococcal meningitis (per 100,000-year)c     
   < 2 months 12.1 9.7-14.5 Not varied Estimated
   2-11 months 5.2 4.2-6.2 Not varied Estimated
   12-59 months 0.5 0.4-0.6 Not varied Estimated
Ratio of incidence of childhood meningitis to sepsis attributable to S. pneumoniae 2.2 1.0-3.4 Triangular [5, 43]
Natural history     
Case-fatality rates     
   Primary endpoint pneumonia 3.0% 2-4% Triangular [9]
   Non-primary endpoint pneumonia 1.1% 0.8-1.4% Triangular [9]
   Meningitis (age-specific)     
< 1 months 27% 20-34% Not varied [41]
1-5 months 23% 17-29% Not varied [41]
6-11 months 48% 36-60% Not varied [41]
12-59 months 46% 35-58% Not varied [41]
   Sepsis 35% 26-44% Triangular [42]
Proportion hospitalized     
Primary endpoint pneumonia 53.0% 40.0-66.3% Triangular [9]
Non-primary endpoint pneumonia 19.3% 14.5-24.1% Triangular [9]
Meningitis 100% 70-100% Uniform Assumed
Sepsis 100% 70-100% Uniform Assumed
Proportion of major disabilities (among disabled due to meningitis) 50% 40-60% Triangular [64]
Vaccine characteristics     
Vaccine coverage (3 doses) 90 82-100 Triangular Assumed
Vaccine serotype coverage     
   PCV7 (4, 6B, 9V, 14, 18C, 19F, 23F) 46% Not varied Not varied [47]
   PCV9 (1, 4, 5, 6B, 9V, 14, 18C, 19F, 23F) 62% Not varied Not varied [47]
   PCV10 (1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, 23F with non-typeable H. influenzae) 62% Not varied Not varied [47]
   PCV13 (1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 23F) 73% Not varied Not varied [47]
Vaccine efficacy against (all-cause) primary endpoint pneumonia     
   PCV7 26% 20-33% Triangular Estimated
   PCV9 & 10 35% 26-44% Triangular [9]
   PCV13 41% 31-51% Triangular Estimated
Vaccine efficacy against (all-cause) non-primary endpoint pneumonia     
   PCV7 -1.1% -2.0 to 0% Triangular Estimated
   PCV9 & 10 -1.5% -2.0 to -1.0% Triangular [9]
   PCV13 -1.8% -2.5 to -2.0% Triangular Estimated
Vaccine efficacy against pneumococcal meningitis/sepsis     
   PCV7 16% 14-18% Triangular Estimated
   PCV9 & 10 22% 19-25% Triangular [8]
   PCV13 26% 22-30% Triangular Estimated
Disability weights     
Meningitis (aged 0-14), episode 0.616 0.462-0.77 Triangular [29]
Meningitis, recovered with long-term disability 0.555 0.416-0.694 Triangular [29]
Pneumonia (aged 0-14), episode 0.28 0.21-0.35 Triangular [29]
Sepsis, episode 0 Not varied Not varied [29]
  1. a This column shows the ranges of parameters that were varied during one-way sensitivity analyses.
  2. b This column shows the distributions assigned to the parameters that were varied during the probabilistic sensitivity analysis. Since data often did not contain enough information from which to estimate distribution parameters, triangular distributions were chosen for a majority of the parameters.
  3. c Annual incidence rates were converted to monthly transition probabilities within the model, assuming an exponential relationship between the cumulative incidence at different time (age) intervals and time (age).
  4. d 95% confidence interval.