Figure 6

Stochastic variation in outbreak dynamics. The results are from 50 runs of the MC simulation; each run has the same input parameters (\({ p_{\mathrm {app}}}= 0.9\), \({\alpha }\cdot {f_{m}}= 0.95\), \({\eta _{as}}= 1\), trace uninfected = true). Top: The fraction of infectious (green), quarantined (blue) and cumulative exposed (yellow) people for each day of the simulated outbreak. Curves for only 20 out of the 50 runs are shown to improve legibility. Outcomes from one selected run are drawn as bold lines. Middle: \({R_{e}}\) each day is shown for the MC run drawn in bold in the top plot. The red vertical line indicates the time when 0.4% of the population have been infected, which is when interventions (other than quarantining of reported symptomatic cases, which is enabled from the beginning) are turned on. To measure their effectiveness, \({R_{e}}\) is averaged over 18 days (red area), starting 10 days after interventions commence. Bottom: Outcomes from the 50 MC runs, such as the maximum fraction of the population quarantined, are histogramed to show the statistical variation more clearly