Indeed, a highly skewed frequency distribution of the number of contacts per person has some astonishing effects on the transmission of infection diseases and on the effect of interventions [1] . In contrast to the results with an assumption of a homogeneous mixing population, the disease transmission is only marginally reduced if a percentage of individuals is immunized at random and, thus, "removed" from the transmission network. In the presence of highly connected individuals, even the celebrated basic reproduction number R 0 , originally defined as "the average number of secondary cases caused by a single index case in a completely nonimmune homogenously mixing population where no interventions are taken", no longer predicts whether an outbreak can occur or not [8, [10] [11] [12] [13] .