Effects of travel restrictions on epidemic severity.
High levels of international travel restrictions are necessary to reduce the total number of infected individuals worldwide. There is little difference in effect between sequential, city-by-city implementation of travel restrictions and simultaneous, worldwide implementation. Results are shown for an epidemic with R0 = 1.7 starting in Hong Kong on July 1. (blue: sequential travel restrictions; red: simultaneous travel restrictions, mean values shown, error bars = 95% confidence intervals)