Volume 34 March 2021
Research article Open access
Optimised prophylactic vaccination in metapopulations
Mingmei Teo, Nigel Bean, Joshua V. Ross
:: A flexible SIR stochastic metapopulation model is studied.
:: Insights to when it is best to allocate vaccines (pre-versus post-outbreak) and to whom they should be allocated are provided.
:: In practice it is generally optimal to distribute all vaccines prophylactically, rather than withholding vaccines.
:: An approximately optimal vaccination scheme is introduced and is shown to be consistently at least as good as three strategies reported in the literature.
A highly effective method for controlling the spread of an infectious disease is vaccination. However, there are many situations where vaccines are in limited supply. The ability to determine, under this constraint, a vaccination strategy which minimises the number of people that become infected over the course of a potential epidemic is essential. Two questions naturally arise: when is it best to allocate vaccines, and to whom should they be allocated? We address these questions in the context of metapopulation models of disease spread. We discover that in practice it is generally optimal to distribute all vaccines prophylactically, rather than withholding until infection is introduced. For small metapopulations, we provide a method for determining the optimal prophylactic allocation. As the optimal strategy becomes computationally intensive to obtain when the population size increases, we detail an approximation method to determine an approximately optimal vaccination scheme. We find that our approximate strategy is consistently at least as good as three strategies reported in the literature across a wide range of parameter values.