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 | 2Â days | [32] |
External infection probability | 0.0003/year | Assumed |
Duration of the infectious period | Â | [32] |
- children (age 0–17 years) | 4 days | |
- adults (age 18Â years and above) | 2Â days | |
Duration of maternal protection | 2 - 4Â months | |
Immunity loss rate after infection (irrespective of influenza subtype or lineage) | 1/(9.13Â years) | Calculated from [31] |
Average circulation time per drift variant | Â | |
- A(H1N1), B/Vic, B/Yam | 7.0Â years | |
- A(H3N2) | 3.5Â years | |
Vaccination coverage | Â | [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, 60Â years of age or older | 48.8% | |
- risk group, 0.5-59 years of age | 33.0% | |
- risk group, 60Â years of age or older | 64.9% | |
Revaccination preference factor | 2 | Assumed |
Probability of mismatched vaccine design when a new drift variant occurs | 40% | |
Vaccine efficacy (well-matched vaccine; irrespective of influenza subtype or lineage) | Â | Â |
- 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] |
- 65Â years of age or older | 58% | [41] |
Cross protection after infection | Â | 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 | Â | 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/(1.8Â years) | Calculated from [44] |
Percentage of the population with elevated risk | Â | [43] |
- newborn individuals | 3.0% | |
- age 0 to 15Â years | 6.0% | |
- age 16 to 59Â years | 14.2% | |
- age 60Â years and above | 47.1% |