Table 2 Model variables.
From: The challenges of containing SARS-CoV-2 via test-trace-and-isolate
Variable | Meaning | Units | Explanation |
|---|---|---|---|
Ha | Hidden asymptomatic pool | People | Non-traced, non-isolated people who are asymptomatic or avoid being tested |
Hs | Hidden symptomatic pool | People | Non-traced, non-isolated people who are symptomatic |
Ta | Traced asymptomatic pool | People | Known infected and isolated people who are asymptomatic |
Ts | Traced symptomatic pool | People | Known infected and isolated people who are symptomatic |
H | Hidden pool | People | Total non-traced people: H = Ha + Hs |
T | Traced pool | People | Total traced people: T = Ta + Ts |
N | New infections (traced and hidden) | Cases day−1 | Given by: \(N={{\Gamma }}\left(\nu +\epsilon \right){R}_{t}^{H}T+{{\Gamma }}{R}_{t}^{H}H+{{\Phi }}\) |
\({\hat{N}}^{\text{obs}}\) | Observed new infections (influx to traced pool) | Cases day−1 | Only cases of the traced pool; delayed on average by 4 days because of reporting |
\({\hat{R}}_{t}^{\,\text{eff}\,}\) | Estimated effective reproduction number | – | Estimated from the cases of all pools: \({\hat{R}}_{t}^{\,\text{eff}\,}=N(t)/N(t-4)\) |
\({\hat{R}}_{t}^{\,\text{obs}\,}\) | Observed reproduction number | – | The reproduction number that can be estimated only from the observed cases: \({\hat{R}}_{t}^{\,\text{obs}\,}={\hat{N}}^{\text{obs}}(t)/{\hat{N}}^{\text{obs}}(t-4)\) |
