Background Following nearly two decades of increasing tuberculosis in the UK, TB incidence decreased by 32% from 2011 to 2015. Explaining this reduction is crucial to informing ongoing TB control efforts.
Methods We stratified TB cases notified in the UK and TB cases averted in the UK through pre-entry screening (PES) between 2011 and 2015 by country of birth and time since arrival. We used population estimates and migration data to establish denominators, and calculated incidence rate ratios (IRRs) between 2011 and 2015. We calculated the contribution of changing migrant population sizes, PES and changes in TB rates to the reduction in TB notifications.
Results TB IRRs fell in all non-EU migrant and UK-born populations between 2011 and 2015 (0.61; 95% CI 0.59 to 0.64 and 0.78; 0.73 to 0.83 respectively), with the greatest decrease in recent non-EU migrants (0.54; 0.48 to 0.61). 61.9% of the reduction in TB notifications was attributable to decreases in TB rates, 33.4% to a fall in the number of recent/mid-term non-EU migrants and 11.4% to PES. A small increase in notifications in EU-born migrants offset the reduction by 6.6%.
Conclusions Large decreases in TB rates in almost all populations accounted for the majority of the reduction in TB notifications, providing evidence of the impact of recent interventions to improve UK TB control. The particularly large decrease in TB rates in recent non-EU migrants provides evidence of the effectiveness of screening interventions that target this population. These findings will inform ongoing improvements to TB control.
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Contributors HLT, RJH, MCM, JAD, MKL, CNJC and DZ contributed substantially to study conception and design, interpretation of data and revising and editing of the manuscript. In addition, HLT proposed the initial idea for the study and wrote the first draft of the manuscript. MCM and JAD acquired and organised the data and RJH did the statistical analysis. SRA contributed to interpretation of the data and revision and editing of the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests DZ is head of the Tuberculosis Screening Unit at Public Health England and has shared responsibilities for quality assurance within the UK pre-entry screening programme and leading on the national latent TB screening programme in England. SRA is head of the Public Health England National TB Programme Office. Other authors have no competing interests to declare.
Patient consent Not required. Public Health England has authority under the Health and Social Care Act 2012 to hold and analyse national surveillance data (including tuberculosis pre-entry screening programme data) for public health and research purposes.
Provenance and peer review Not commissioned; externally peer reviewed.
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