Figure 6:

Schematic illustration of the factor c(t), representing the effect of NPIs and adaptive behavioural changes on transmission. L₁ represents the known duration (and timing) of the first lockdown as imposed by governments. T₀ is the number of days in the series prior to the gradual contact reductions early in the pandemic (estimated). T₁ (> T₀) is the day the first lockdown begins (informed by data). T₂ is the number of days for the ramp of increasing transmission after first lockdown to return to baseline c(t) = 1 and determines the slope that distinguishes the two panels: (a) T₂ → ∞; (b) T₂ = 120 days.