Influence of the Removal of Highly Connected Individuals on the Maximum Eigenvalue of the Next Generation Matrix of the Remaining Casual Contact Network. The curve shows median values of 100 simulations, given in arbitrary units. Red and yellow curves: Individuals are first sorted by their number of contacts; the removal starts with the person who has most contacts and progresses towards less highly connected ones. (a) Red curve: the horizontal axis shows what percentage of the population has been removed. (b) Yellow curve: as before, but a random sample of 90% of the selected individuals is removed. (c) Blue curve: people are not pre-sorted by their number of contacts, but are removed at random.