Vaccine X
An age-stratified mathematical model to inform optimal measles vaccination strategies
By Samiran Ghosh, Indrajit Ghosh and Siuli Mukhopadhyay.
Abstract
Background
Measles remains a significant global public health threat despite the availability of an effective vaccine. WHO recommends the first measles vaccine dose at 9–12 months of age, balancing maternal antibody interference and immune system maturity. However, infants younger than 9 months remain highly vulnerable, especially in regions with high transmission and low herd immunity.
Methods
This study introduces an age-stratified, multi-compartmental model of measles transmission that captures infections in unvaccinated infants by explicitly modelling maternal immunity decay and early infection risks. We prove the model’s positivity and derive an analytical expression for the instantaneous replacement number. For a non-age-stratified version, we analyze equilibrium points and their stability. We also conducted a global sensitivity analysis of the model parameters with respect to the aggregate incidence of measles over 30 years. Further, using a bootstrap algorithm, critical parameters and age-specific transmission rates are identified by fitting the model to yearly incidence data from six measles-prevalent countries.
