Table 1.
Variables used in economic model
| Variables | Expected value | Distribution | Reference |
|---|---|---|---|
| Age specific incidence | See appendix 8 in supplementary file | NA | See methods |
| Odds of IPD* | Age and risk group dependent* | Log normal | 7, see methods |
| Case fatality ratio† | Age and risk group dependent† | β | 7, see methods |
| Share of meningitis in total burden of IPD | 3-8% (age dependent) | Fixed | See methods |
| Share of empyema in total burden of IPD | 1-5% (age dependent) | Fixed | See methods |
| Vaccine efficacy against IPD‡ | |||
| High risk immunocompetent: | |||
| <65 years | 0.71 | β (α 2.1, β 0.863) | See methods |
| ≥65 years | 0.63 | β (α 2.01, β 1.19) | See methods |
| High risk immunocompromised: | |||
| <65 years | 0.53 | β (α 1.59, β 1.41) | See methods |
| ≥65 years | 0.43 | β (α 1.21, β 1.62) | See methods |
| Vaccine efficacy against non-bacteraemic pneumococcal pneumonia‡ | |||
| High risk immunocompetent: | |||
| <65 years | 0.46 | β (α 1.88, β 2.19) | See methods |
| ≥65 years | 0.40 | β (α 1.47, β 2.2) | See methods |
| High risk immunocompromised: | |||
| <65 years | 0.33 | β (α 1.24, β 2.55) | See methods |
| ≥65 years | 0.27 | β (α 1.27, β 3.47) | See methods |
| Waning immunity (per year)§ | |||
| Immunocompetent: | |||
| <65 years | 0.11 | See methods | See methods |
| ≥65 years | 0.25 | See methods | See methods |
| Immunocompromised: | |||
| <65 years | 0.24 | See methods | See methods |
| ≥65 years | 0.26 | See methods | See methods |
| Prevalence of sequelae after meningitis | |||
| Deafness | 0.08 | β (mean 0.08 SE 0.03) | 9 |
| Mild hearing loss | 0.21 | β (mean 0.21 SE 0.02) | 9 |
| Seizures and hydrocephalus | 0.07 | β (mean 0.07 SE 0.02) | 9 |
| Spasticity or paresis | 0.09 | β (mean 0.09 SE 0.01) | 9 |
| Cranial nerve palsy | 0.12 | β (mean 0.12 SE 0.04) | 9 |
| Quality adjusted life year losses | |||
| Hospital admission for meningitis | 0.023 | β (mean 0.023 SE 0.031) | 21 20 |
| Hospital admission for bacteraemia¶ | 0.0079 | β (mean 0.079 SE 0.083) | 21 |
| Hospital admission for non-bacteraemic pneumonia | 0.006 | Normal (mean 0.006 SD 0.0015) | 21 20 |
| Quality of life weights | |||
| Deafness | 0.81 | β (mean 0.81 SE 0. 028) | 22 |
| Mild hearing loss | 0.91 | β (mean 0.91 SE 0.015) | 22 |
| Seizures | 0.83 | β (mean 0.83 SE 0.015) | 22 |
| Hydrocephalus | 0.62 | β (mean 0.62 SE 0.021) | 22 |
| Spasticity or paresis | 0.67 | β (mean 0.67 SE 0.023) | 22 |
| Cranial nerve palsy | 0.67 | β (mean 0.67 SE 0.023) | 22 |
| Costs (£) | |||
| Case of meningitis** | 6509 | Normal (mean 6509 SD 405) | See methods |
| Case of empyema** | 7538 | Normal (mean 7665 SD 444) | See methods |
| Short hospital stay for other IPD** | 825 | Normal (mean 839 SD 3.93) | See methods |
| Long hospital stay for other IPD: | |||
| With excess days in hospital** | 8977 | Normal (mean 9129 SD 142) | See methods |
| Without excess days in hospital** | 3022 | Normal (mean 3073 SD 19) | See methods |
| Admitted to hospital for pneumonia | 661 | Normal (mean 672 SD 168) | See methods |
| Chance of long stay for IPD | 0.61 | β (α 5075 β 8257) | See methods |
| Chance of excess days during long stay for IPD | 0.46 | β (α 2328 β 5075) | See methods |
| Lifetime costs after meningitis: | |||
| In first year | 6591 | Log normal (mean 8.7 SD 0.4) | 24 |
| In subsequent years | 203 | Log normal (mean 8.7 SD 0.4) | 24 |
| Outpatient follow-up for meningitis | 382 | Log normal (mean 5.2 SD 0.4) | 24 |
| Cost of 13 valent pneumococcal conjugate vaccine | 49.10 | Fixed | 42 |
| Administration costs | 7.51 | Fixed | 42 |
| Other variables | |||
| Herd effect due to infant vaccination | See appendix 2 in supplementary file | Normal | See appendix 2 in supplementary file |
| Life expectancy among high risk groups | See appendix 2 in supplementary file | NA | See methods |
| Discount rate for costs and health effects | 3.5% | NA | 25 |
IPD=invasive pneumococcal disease; £1.00 ($1.6; €1.2).
*Odds ratio of IPD comparing risk groups to non-risk groups. Specific odds ratios can be found in Van Hoek et al.7
†Age specific case fatality ratios can be found in Van Hoek et al.7
‡After single dose during first year of vaccination. Efficacy estimates do not apply for serotype 3 (see method section).16 Estimates of vaccine efficacy after two doses are listed in appendix 4 in the supplementary file.
§Annual waning factor was calculated by using the experts’ estimation of vaccine efficacy during first and third year after vaccination using annual exponential decay of immunity.
¶Same quality of life year decrement was assumed for invasive pneumonia, bacteraemia with focus, and bacteraemia without focus.
**Mean costs were sampled from a normal distribution with a mean equal to the log normal mean and standard deviation equal to the standard error of the log normal mean.