Parameters
Description | Symbol* | Base-case (sensitivity values/distribution) | Source |
Disease model | |||
No of serotypes | Z | 15 | |
Under-five colonisation prevalence fitted to | 40% | Authors’ assumption based on41–48 50 65 | |
Contact rate | β | Fitted to under-five colonisation prevalence | |
Immigration force of infection | W | 1e−06 | As in37 |
Intrinsic duration of carriage for serotype z | γ(z) | 25–220 days (linearly increasing across serotypes) | As in37 and based on66 67 |
Reduction in susceptibility to Pneumococcus from carrying the fittest serotype | μmax | 0.25 | As in37 |
Reduction in susceptibility to a serotype conferred by prior carriage of that serotype | σ | 0.5 (0.5, 0.8) | ≥0.5 based on results for Z=15 in37 |
Shape parameter for the reduction in duration of carriage dependent on past colonisation | ε | 0.1 (0.1, 0.25 and 0.4) | Based on37 |
Case–carrier ratio (pneumococcal pneumonia, meningitis and other invasive pneumococcal disease) | Fitted to disease incidence given colonisation prevalence | Based on5 52 65 68 | |
Case fatality rate | Fitted to death rate | Based on5 51 52 65 | |
Treatment | |||
Seek treatment | Wealth quintile I: 48%; II: 51%; III: 60%; IV: 66%; V: 75% | Based on34 35 69 | |
Probability seek care at public provider (if seek care) |
| ||
Receive appropriate treatment at health provider | 95% | Authors’ assumption | |
Inpatient meningitis cost | Based on54 69 70 | ||
Public providers | US$191 (triangular min=US$134, max=US$248, mode=US$191) | ||
Private providers | US$275 (triangular min=US$193, max=US$358, mode=US$275) | ||
Inpatient pneumonia cost | Based on54 69 71 | ||
Public providers | US$93 (triangular min=US$65, max=US$121, mode=US$93) | ||
Private providers | US$214 (triangular min=US$150, max=US$278, mode=US$214) | ||
Inpatient other pneumococcal disease cost | Based on54 69 | ||
Public providers | US$76 (triangular min=US$53, max=US$99, mode=US$76) | ||
Private providers | US$194 (triangular min=US$136, max=US$252, mode=US$194) | ||
Outpatient cost | Based on54 69 | ||
Public providers | US$7.55 (triangular min=US$5.30, max=US$9.80, mode=US$7.55) | ||
Private providers | US$9.47 (triangular min=US$6.60, max=US$9.80, mode=US$12.30) | ||
Unattended pneumonia cost | US$1.05 (triangular min=US$0, max=US$1.40, mode=US$1.05) | 72 | |
Antibiotics clear colonisation or symptomatic infection | 50% | Authors’ assumption based on73–75 | |
Exogenous antibiotic prescription rate (per day) | 0.001327 | Based on IMS Health MIDAS database | |
Vaccine | |||
PCV13 % of cases | Most common serotypes representing approximately 70% | Based on38 56 | |
Per-person vaccine efficacy | p | 0.6 | As in37, estimated using76 |
Per-child cost in scenario 1† | US$13.60 (triangular min=US$6.35, max=US$18.95, mode=US$13.60) | Based on WHO cMYP tool | |
Per-child cost in scenario 2† | US$13.50 (triangular min=US$6.25, max=US$18.85, mode=US$13.50) | Based on WHO cMYP tool |
Values varied for sensitivity are in parentheses. Costs in 2014 US dollars.
*Symbols for Cobey and Lipsitch 2012 model.
†Three doses at US$3.30 per dose and training, syringe, wastage costs (5% vaccine wastage rate and 10% syringe wastage rate) and a 25% buffer stock. Ranges for the sensitivity assume US$1 to US$5 per dose.
cMYP, comprehensive multiyear plan; PCV, pneumococcal conjugate vaccine.