Table 1.
Description of the SEIR-v model parameters.
| Parameter | Unit | Description | Value | Comments |
|---|---|---|---|---|
| N | N People | Population | 67,838,235 [15] | Total population in the UK as of 2020 |
| Ev 0 | N People | Vulnerable Exposed | 2 | Vulnerable individuals exposed to the disease at the beginning of the outbreak |
| E 0 | N People | Exposed | 4 | Non-vulnerable individuals exposed to the disease at the beginning of the outbreak |
| Iv 0 | N People | Infected | 0 | Vulnerable infected individuals at the beginning of the outbreak |
| I 0 | N People | Infected | 1 | Non-vulnerable infected individuals at the beginning of the outbreak |
| Tinc | Days | Incubation period | 5.6 [16] | σ = 1/Tinc, where Tinc is the time it takes for an exposed individual to become infectious |
| Tlat | Days | Latent period | 7.5 [16] | γ = 1/Tlat, where Tlat is the time it takes for an infectious individual to recover |
| µv | Vulnerable deaths/Vulnerable Infected | Vulnerable Case Fatality Rate | [0.005–0.037, 95% CI]% | Case fatality rate of COVID-19 on vulnerable individuals |
| µ | Non-vulnerable deaths/non-vulnerable Infected | Non-vulnerable Case Fatality Rate | [0.000007–0.000011, 95% CI]% | Case fatality rate of COVID-19 on non-vulnerable individuals |
| pv | *- | Vulnerable probability | 0.2 | Probability of an individual being vulnerable to the disease |
| η | *- | Fear Factor | 0.33 | Fear factor caused by the recommendation made by the UK government for vulnerable individuals to stay at home for at least 12 weeks at the beginning of the outbreak and the widespread severity of the disease within this group |
| β 0 | 1/(person*day) | Initial Contact Rate | [0.5–2.1, 95% CI] | Contact rate at the beginning of the outbreak |
| β 1 | 1/(person*day) | Contact Rate 1 | [0.9–0.95, 95% CI] * β0 | Contact rate after the mandate of case-based self-isolation |
| β 2 | 1/(person*day) | Contact Rate 2 | [0.9–0.95, 95% CI] * β1 | Contact rate after government encouragement for social distancing |
| β 3 | 1/(person*day) | Contact Rate 3 | [0.75–0.85, 95% CI] * β2 | Contact rate after schools closure |
| β 4 | 1/(person*day) | Contact Rate 4 | [0.40–0.60, 95% CI] * β3 | Contact rate after lockdown order and banning of public events |
| β 5 | 1/(person*day) | Contact Rate 5 | [1.1–1.9, 95% CI] * β4 | Contact rate after recommendation for people to go back to work |
| βvi | 1/(person*day) | Vulnerable Contact Rate | η * βi | Contact rate of vulnerable individuals. |
*- Dimensionless.