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Table 1 List of parameters and baseline values
| Parameter | Baseline | Reference |
|---|---|---|
| Basic reproduction number R 0 | 1.575 | Calibration |
| Maximum seasonal transmission factor | 1.43 | [31] |
| Day of maximum seasonal transmission | Dec. 21st | [31] |
| Duration of the latent period | 2 days | [32] |
| External infection probability | 0.0003/year | Assumed |
| Duration of the infectious period | [32] | |
| - children (age 0–17 years) | 4 days | |
| - adults (age 18 years and above) | 2 days | |
| Duration of maternal protection | 2 - 4 months | [33, 34] |
| Immunity loss rate after infection (irrespective of influenza subtype or lineage) | 1/(9.13 years) | Calculated from [31] |
| Average circulation time per drift variant | Calculated from [35] and [3] | |
| - A(H1N1), B/Vic, B/Yam | 7.0 years | |
| - A(H3N2) | 3.5 years | |
| Vaccination coverage | [38] | |
| - no risk group, 0.5-2 years of age | 19.2% | |
| - no risk group, 3–6 years of age | 22.4% | |
| - no risk group, 7–10 years of age | 23.6% | |
| - no risk group, 11–15 years of age | 11.0% | |
| - no risk group, 16–59 years of age | 16.9% | |
| - no risk group, 60 years of age or older | 48.8% | |
| - risk group, 0.5-59 years of age | 33.0% | |
| - risk group, 60 years of age or older | 64.9% | |
| Revaccination preference factor | 2 | Assumed |
| Probability of mismatched vaccine design when a new drift variant occurs | 40% | Calculated from [3, 35, 42] |
| Vaccine efficacy (well-matched vaccine; irrespective of influenza subtype or lineage) | ||
| - 0–1 year of age | 45% | [40] |
| - 2–5 years of age | 39% | [40] |
| - 6–15 years of age | 69% | [40] |
| - 16–64 years of age | 73% | [39] |
| - 65 years of age or older | 58% | [41] |
| Cross protection after infection | Calculated from [39] | |
| - percentage of individuals who are immunized against a B lineage when they are infected (or booster-infected) with the other B lineage (lineage cross protection) | 60% | |
| - percentage of individuals who were immune against the previous drift variant, who are still protected against the new one (drift cross protection) | 60% | |
| Cross protection after vaccination | Calculated from [39] | |
| - vaccine efficacy multiplication factor for B lineage not contained in TIV (lineage cross protection) | 0.6 | |
| - vaccine efficacy multiplication factor for vaccinations with drift mismatch (drift cross protection) | 0.6 | |
| Immunity loss rate after vaccination | 1/(1.8 years) | Calculated from [44] |
| Percentage of the population with elevated risk | [43] | |
| - newborn individuals | 3.0% | |
| - age 0 to 15 years | 6.0% | |
| - age 16 to 59 years | 14.2% | |
| - age 60 years and above | 47.1% |
