The effect of social networks on the participation by those with parental responsibility in the baby immunisation programme in the UK

Abstract

The majority of UK parents participate in the recommended baby vaccination programme, but some vaccines (notably MMR) have uptake below levels recommended to control outbreaks of vaccine-preventable disease, and this risk increases if the unvaccinated children are clustered. We explored the hypothesis that vaccination decisions made by parents based on information shared peer-to -peer could create clusters of opinions, and contribute to local vaccine uptake variations. Ecological analysis of MMR uptake on a small spatial scale confirmed uneven coverage and a while a regression model showed uptake was associated with ethnicity and extremes of education, overall the observations were poorly explained by demographic factors. Mathematical modelling of decisions influenced by sharing information confirmed this process is theoretically able to create opinion clusters and changes in the proportions intending to vaccinate, but that results are qualitatively and quantitatively sensitive to network structure and decision representation. This uncertainty could not be resolved for UK baby vaccinations with existing data, so a survey was undertaken to address the knowledge gaps. Data were gathered on parents’ networks of vaccine-information providers and on other variables within the MMR-measles decision-infection system, including social contacts for preschool children (with a larger sample than provided by all-age studies). The survey provided evidence of individual-level vaccination-behaviour clustering and informed revised mathematical models using empirically-supported network structures and decision representation. These simulations showed the UK conditions could enable information-sharing to create increased opinion clustering and to shift population-level vaccination sentiment (increasing those supporting schedule adherence). Through an integrated programme of statistical analysis, data collection and mathematical modelling this thesis provides evidence to confirm the presence of clusters of vaccine opinion and to support the hypothesis that an information-sharing process is able to increase opinion clustering, albeit in a manner requiring further investigation to ascertain the associated relative outbreak risk.