Figure 1
A scenario for time-dependent increase in the transmission potential. A. Time dependent increase in the transmission rate. In the absence of intervention (baseline scenario), the transmission rate is assumed to be constant β over time. In the presence of early intervention, the transmission rate is reduced by a factor α (0 ≤ α ≤ 1) over time interval 0 to t1. We assume that the product αβ ileads to super-critical level (i.e. αR(0) > 1 where R(0) is the reproduction number at time 0), and t1 occurs before the time at which peak prevalence of infectious individuals in the absence of intervention is observed. B. A comparison between two representative epidemic curves (the number of infectious individuals) in a hypothetical population of 100,000 individuals. R(0) = 1.5, α = 0.90 and t1 = 50 days. The epidemic peak in the presence of short-lasting control is delayed, and the height of epidemic curve is slightly reduced, relative to the case in which control measures are absent.