How population heterogeneity in susceptibility and infectivity influences epidemic dynamics.
An important concern in public health is what population group should be prioritised for vaccination. To this end, we present an epidemic model with arbitrary initial distributions for population susceptibility, and corresponding infectivity distributions. We consider four scenarios: first, a population with heterogeneous susceptibility with a uniform distribution, but homogeneous infectivity; second, a heterogeneously susceptible population with linear heterogeneous infectivity functions, where the most susceptible are either the most or least infectious; third, a bimodal distribution for susceptibility, with all combinations of infectivity functions; finally, we consider the effects of additional pre-epidemic immunity, ostensibly through vaccination, on the epidemic dynamics. For a seasonal influenza-like infectious disease, we find the smallest final size and overall number of deaths due to the epidemic to occur if the most susceptible are vaccinated, corresponding to targeting children.
School of Mathematical & Physical Sciences, University of Newcastle, Callaghan, NSW 2308, Australia. Electronic address: r.hickson@UNSWalumni.com.
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Hickson
Institute of Natural & Mathematical Sciences, New Zealand Institute for Advanced Study and Infectious Disease Research Centre, Massey University, Private Bag 102 904, North Shore Mail Centre, Auckland, New Zealand. Electronic address: m.g.roberts@massey.ac.nz.
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Roberts
D003141:Communicable Diseases / Q000453:epidemiology*; D004198:Disease Susceptibility / Q000453:epidemiology*; D058872:Epidemics / Q000706:statistics & numerical data*; D006801:Humans; D011157:Population Dynamics; D014611:Vaccination
Epidemic; Final size; Heterogeneous population; Infectious diseases; Vaccination