Table 2. Characteristics and summary statistics of the main experiment and sensitivity analyses.
| Description of parameter(s) alterations | ORI rate in 10–14 age groupa per model run- years | Outbreak rate in all agesb per model run-years | Outbreak rate in under 1b per model run-years | Outbreak rate in 10–14 age groupb per model run- years | Comparability with benchmark cumulative incidencec | |
|---|---|---|---|---|---|---|
| Main experiment | Reference | 0.038 | 0.315 | 0.075 | 0.129 | Yes |
| Sensitivity analysis A | Increase vaccine coverage for dose 7 by 20% | 0.037 | 0.315 | 0.080 | 0.127 | Yes |
| Sensitivity analysis B | Increase value of (τ) to 3 among those born before 1997 | 0.039 | 0.323 | 0.075 | 0.127 | Yes |
| Sensitivity analysis C | Increase value of (α) to 10 | 0.040 | 0.341 | 0.082 | 0.135 | Yes |
| Sensitivity analysis D | Restrict ORI eligibility to those who did not receive vaccine within last 6 months | 0.036 | 0.324 | 0.078 | 0.129 | Yes |
| Sensitivity analysis E | Implement stronger vaccine boosting effect | 0.005 | 0.047 | 0.013 | 0.021 | No |
| Sensitivity analysis F | Multi-way sensitivity analysis B and C combined | 0.025 | 0.325 | 0.083 | 0.129 | Yes |
Notes.
ORI rate is computed by dividing the number of triggered ORIs by the product of a total number of simulation runs in a given experiment and 30 years in each run. Reciprocal of the ORI rate represents mean time between occurrences of triggering ORIs; for example, the rate of 0.038 per model run-years in the main experiment indicates that ORI in the 10–14 age group was triggered every 26 years in the model (1∕0.038 = 26.3).
Outbreak rate is computed by dividing the number of outbreaks within a specified age group (or when judged with respect to all age groups) by the product of a total number of simulation runs in a given experiment and 30 years in each run. Reciprocal of the outbreak rate represents the mean period between outbreaks occurring within a given age group; for example, the rate of 0.315 per model run-years in the main experiment indicates that outbreaks in all age groups were occurring every 3 years in the model (1∕0.315 = 3.17).
Comparability with benchmark cumulative incidence was defined as model-generated 30-years cumulative incidence rate falling within 10% of the average empirical cumulative incidence rate derived from 15 years of observations in two jurisdictions in Alberta (15 years of observations were up-scaled to derive 30-year cumulative incidence).