Identifying inequalities in childhood immunisation uptake and timeliness in southeast Scotland, 2008-2018: A retrospective cohort study.

BACKGROUND

In 2018, there was a record incidence of measles and other vaccine-preventable diseases across developed countries. Declining childhood immunisation uptake in southeast Scotland-an area with a large, highly mobile, and socioeconomically diverse population-threatens regional herd immunity and warrants investigation of suboptimal coverage. As deprivation of social and material resources increases risk of non-vaccination, we examined here the relationship between deprivation, uptake, and timeliness for four routine childhood vaccines and identified trends over the past decade.

METHODS

This retrospective cohort study analysed immunisation data from the Scottish Immunisation Recall System (SIRS) for four routine childhood vaccines in the UK: the third dose of the primary vaccine (TPV), both doses of measles, mumps, rubella (MMR 1 and MMR 2), and the preschool booster (PSB). Immunisations (N = 329,897) were administered between 2008 and 2018. Deprivation was measured via the Scottish Index of Multiple Deprivation (SIMD), ranking postcodes by deprivation decile. Chi-squared tests and cox proportional hazards models assessed the relationship between uptake, timeliness, and deprivation.

RESULTS

There is strong evidence for an association between deprivation, uptake, and timeliness. Uptake for all childhood immunisations are very high, especially for TPV and MMR 1 (>98.0%), though certain deprivation deciles exhibit increased risks of non-vaccination for all vaccines. Delay was pronounced for the 40% most deprived population and for immunisations scheduled at later ages. Absolute PSB and MMR 2 uptake has improved since 2008; however, disparities in uptake have increased for all vaccines since the 2006 birth cohort.

CONCLUSION

Both timeliness and uptake are strongly associated with deprivation. While absolute uptake was high for all vaccines, relative uptake and timeliness has been worsening for most groups; the reason for this decline is unclear. Here we identified subgroups that may require targeted interventions to facilitate uptake and timeliness for essential childhood vaccines.