Parameter | Description | Base-case value | Reference |
---|---|---|---|
R 0 | Basic reproduction number | 1.6 | Chowell et al. [20]; expert opinion |
z | Amplitude of seasonal transmission | 43% | Vynnycky et al. [21] |
α | Outside infection rate (per person per year) | 0.001 | Assumption |
D L | Average duration of the latent period (days) | 1 | Carrat et al. [22] |
D I | Average duration of the infectious period (days) | 5 | Carrat et al. [22] |
f K | Symptomatic fraction of infected individuals | 66.9% | Carrat et al. [22] |
f med | Fraction of symptomatic cases who seek medical help (i.e. physician consultation) | ||
- children below 2 years of age | 60% | Expert opinion | |
- children from 2 to 6 years of age | 40% | Expert opinion | |
- children from 7 to 12 years of age | 30% | Expert opinion | |
- juveniles from 13 to 17 years of age | 10% | Expert opinion | |
- adults below 60 years of age without increased risk | 20% | Expert opinion | |
- adults with increased risk or above 60 years of age | 50% | Expert opinion | |
f R | Immune fraction before initialising the simulations | 45% | Assumption |
m | Fraction of newborns protected by maternal antibodies | 30% | Assumption |
D M | Average duration of maternal protection (months) | 4 | Expert opinion |
| Average duration of naturally acquired immunity to influenza A (years) | 6 | Vynnycky et al. [21] |
| Average duration of naturally acquired immunity to influenza B (years) | 12 | Vynnycky et al. [21] |
D TIV | Average duration of TIV induced immunity (years) | 0.7 | Assumption |
D LAIV | Average duration of LAIV induced immunity (years) | 2.8 | Guided by Tam et al. [26] |
r 18–44 | Percentage of people from 18 to 44 years of age with elevated risk | 7.6% | Fleming & Elliott [25] |
r 45–59 | Percentage of people from 45 to 59 years of age with elevated risk | 17.6% | Fleming & Elliott [25] |