To test the efficiency of targeted immunization strategies on real networks, we used interaction data of individuals at five different universities in the US taken from a social network website [41] , and obtained the contact network relevant for directly transmissible diseases (see Methods). We find again that the overall most successful targeted immunization strategy is the one that identifies the targets based on random walk centrality. Limited immunization based on random walk centrality significantly outperforms immunization based on degree especially when vaccination coverage is low (Figure 5a ).