Fig. 4From: Timeliness of contact tracing among flight passengers during the COVID-19 epidemic in VietnamThe cumulative probability of unsuccessful tracing for 1812 passengers on 22 flights during March 2020. * Survival probability was estimated using Kaplan Meier and interpreted as probability of successful tracing. Note: Dotted red lines indicated the 95% confidence intervals. The black dashed line indicates the time when half of all passengers are expected to be tracedBack to article page