Modelling measles and mumps outbreak risk across Wales using synthetic small area estimation

Abstract

Measles and mumps are two of the most commonly occurring vaccine-preventable diseases in the developed world. In Wales, outbreaks of both diseases have been witnessed since the turn of the century, with the number of those affected reaching well into the thousands. The combined measles, mumps and rubella vaccine (MMR), has been the primary source of protection from these diseases since its introduction to the Welsh vaccination programme in 1988. Understanding whether socio-economic factors influence the uptake of this vaccine, and to what degree, may be of importance in accounting for spatial disparities regarding the relative risk of measles and mumps outbreaks across Wales.

This study attempts to understand some of the socio-economic risk factors of low uptake of the MMR vaccine across Wales, using census variables in combination with both univariate and multivariate linear regression analyses, in order determine potential ecological risk factors. The study uses a Synthetic Small Area Estimation approach to estimate the uptake of the MMR vaccine across Wales at MSOA level, using census socio-economic variables in combination with COVER MMR uptake data. Spatial accessibility is also explored as a potential barrier to vaccination, and examined across Wales by measuring the cumulative road distance to the nearest NHS registered GP.

The study concludes that there are noticeable geographic variations in terms of the distribution of this risk, and the resulting likelihood of future outbreaks. The results of the model highlight areas that are at increased risk, although it does not account for interaction based models of disease transmission.