Fig. 2: Impact of the notification window length and active app use on transmission.

a The relative probability of the base case testing positive on a given day in their infectiousness profile, obtained by normalising the median (black, solid line) positive test probability profile for LFTs taken by asymptomatic, infected individuals⁷. Normalised 95% credible interval test probability profiles⁷ (upper - red, dashed line; lower - blue, dot-dashed) are also considered, to obtain shaded regions in (b) and (c). b The percentage reduction in R^* for different length notification window w, relative to a scenario in which a notification app is not used, under the assumption that all individuals are active app users (i.e. 100% adherence). c The relationship between the proportion of primary cases who are active app users and the percentage reduction in R^* for a 5-day notification window (blue solid line, circle markers) and a 2-day notification window (orange dotted line, cross markers). d A heat map indicating the transmission reduction achieved by using a 5-day window rather than a 2-day window, quantified by the difference in the percentage reduction in R^* that results from a 5-day notification window compared to a 2-day notification window. The proportion of primary cases assumed to be active app users for a 2-day window is shown on the x-axis, and the relative level of active app use assumed for a 5-day window (compared to the level of active app use for a 2-day window) is shown on the y-axis. Purple (green) regions correspond to where 5-day (2-day) notification windows lead to a larger reduction in R^*.