TABLE 1.
Model parameters and parameter ranges.
| Parameter | Definition | Range of estimates used in calibration step | Estimate or fixed value | |
|---|---|---|---|---|
| v | Duration of immunity (days) | 200–300 | 227 (95% CI: 217, 236) | |
| β 1 | Amplitude of seasonal forcing | 0–1 | 0.245 (95% CI: 0.211, 0.282) | |
| γ | Infectious period (days) | Fixed 18 | 9 | |
| δ | Latent period (days) | Fixed 18 | 4 | |
|
|
Phase shift | 0–2π | 2.011 (95% CI: 1.866, 2.168) | |
| β 0 | Transmission coefficient | 0–1 | 0.033 (95% CI: 0.031, 0.035) | |
| h 1, h 2, h 3, h 4, h 5 | Scaling factors representing the risk of (reported) hospitalization given infection for 0–2 months, 3–5 months, 6–11 months, 12–23 months, and 2+ years | 0–0.5 |
0.073 (95% CI: 0.065, 0.082) 0.020 (95% CI: 0.017, 0.023) 0.010 (95% CI: 0.008, 0.012) 0.003 (95% CI: 0.0027, 0.0035) 0.00004 (95% CI: 0.00003, 0.00005) |
|
| ω | Reduced infectiousness in >10 years old | Fixed 18 | 0.6 | |
| σ 1, σ 2, σ 3 | Reduced infectiousness in >3 months old | Fixed 18 | 0.08, 0.45, 0.45 |
Note: Fixed model parameters and the range of estimates considered for each parameter fit to surveillance data.