Disease control strategies, such as vaccination, aim to reduce disease incidence and therewith the disease costs incurred by a population. However, control strategies also have the indirect effect of changing the age distribution of infected cases. Because the severity and cost of infection are heavily dependent on age for many diseases, control strategies may therefore also impact the economic costs of a disease in this way. Here, we evaluate whether and to what extent these effects are governed by social contact patterns. Our work extends a simple bio-economic framework [Althouse et al 2010 PNAS] by analyzing the implications of different social contact structures on the value of vaccination. We base our analysis on an age structured SIR model with varying degrees of assortativity by age and a given function for how the cost of an infection depends on age.
Results/Conclusions
With this model, we find that the value of a vaccination policy is sensitive to the degree of age assortativity. For diseases that incur a large economic cost to either very young or very old individuals when infected, our results suggest that vaccine subsidies may need to be higher in countries with lower age assortativity than in countries with higher age assortativity. We extend our analysis by considering the contact structure derived from the European POLYMOD study [Mossong et al 2008 Plos Med], together with recent findings that the degree of age assortativity may be lower in developing countries than in European ones [Horby et al 2011 Plos One].