title: A new look at the critical community size for childhood infections.
abstract: Quasi-stationarity and time to extinction are studied for the classic endemic model. Attention is restricted to the transition region in parameter space where the quasi-stationary distribution is non-normal. A new approximation of the marginal distribution of infected individuals in quasi-stationarity is presented. It leads to a simple explicit expression for an approximation of the critical community size in terms of model parameters.
authors.affiliation: Department of Mathematics, The Royal Institute of Technology, 10044 Stockholm, Sweden. ingemar@math.kth.se
authors.forename: Ingemar
authors.initials: I
authors.lastname: Nåsell
mesh_terms: D002648:Child; D002675:Child, Preschool; D003141:Communicable Diseases / Q000453:epidemiology*; D006801:Humans; D015233:Models, Statistical; D012111:Residence Characteristics; D013269:Stochastic Processes