Table 1. Description of model parameters, our baseline parameterisation and the alternative values considered in the univariate sensitivity analysis.
| Description | Baseline | Sensitivity | Source |
|---|---|---|---|
| LFT sensitivity | 30 day positive test probability profile for symptomatics Faster decay in positive test probabilities for asymptomatics (Fig B in S1 Text) |
95% credible intervals from Hellewell et al. [49] for symptomatics Transformed 95% credible intervals from Hellewell et al. [49] for asymptomatics |
[49, 50] |
| PCR sensitivity | As above | As above | [49, 50] |
| within-school transmission, K | Unif(1,5) | Baseline—K = 3 Low—K = 1 High—K = 5 |
Assumption |
| External daily probability of infection to each pupil, ϵ | 0.001 (such that 10% of pupils are infected over a half term) |
Low—0.5 × ϵ
High—2 × ϵ |
Assumption |
| Relative probability of transmission since day of infection, ΓI(d) | Γ(5.62, 0.98) | - | [51] |
| Incubation period (time until symptom onset) |
Γ(5.807, 0.948) | - | [52] |
| % of pupils symptomatic | Unif(12,31) | Baseline—21.5% Low—12% High—31% |
[53] |
| Relative infectiousness of asymptomatic individuals, a (%) | Unif(30, 70) | Baseline—50% Low—30% High—70% |
[54, 55] |
| Initial population level immunity, Rinit | 20% | Low—10% High—30% |
[47] |
| Initial population level prevalence, Iinit | 2% | - | [46] |
| Interaction between year groups, α | 0—i.e. 100% of within-school infections are within-year | 1—i.e. 20% of within-school infections are within-year | Assumption |