|
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%
|
