Background Understanding differences in the seasonality of bronchiolitis can help to plan the timing of interventions. We quantified the extent to which seasonality in hospital admissions for bronchiolitis is modified by socioeconomic position.
Methods Using Hospital Episode Statistics, we followed 3 717 329 infants born in English National Health Service hospitals between 2011 and 2016 for 1 year. We calculated the proportion of all infant admissions due to bronchiolitis and the incidence rate of bronchiolitis admissions per 1000 infant-years, according to year, month, age, socioeconomic position and region. We used harmonic Poisson regression analysis to assess whether socioeconomic position modified bronchiolitis seasonality.
Results The admission rate for bronchiolitis in England increased from 47.4 (95% CI 46.8 to 47.9) to 58.9 per 1000 infant-years (95% CI 58.3 to 59.5) between 2012 and 2016. We identified some variation in the seasonality of admissions by socioeconomic position: increased deprivation was associated with less seasonal variation and a slightly delayed epidemic peak. At week 50, the risk of admission was 38% greater (incidence rate ratios 1.38; 95% CI 1.35 to 1.41) for infants in the most deprived socioeconomic group compared with the least deprived group.
Conclusion These results do not support the need for differential timing of prophylaxis or vaccination by socioeconomic group but suggest that infants born into socioeconomic deprivation should be considered a priority group for future interventions. Further research is needed to establish if the viral aetiology of bronchiolitis varies by season and socioeconomic group, and to quantify risk factors mediating socioeconomic deprivation and bronchiolitis rates.
- respiratory DI
- social epidemiology
- child health
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Correction notice This article has been corrected since it first published online. In table 1, the 'Person-based' admission rates by sex and IMD group have been corrected.
Contributors All authors designed the study and revised the paper. KL cleaned and analysed the data, and drafted the paper. PH supervised the study.
Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors. KL is funded by a UK Medical Research Council doctoral training studentship (MR/N013867/1).
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Date availability statement Data may be obtained from a third party and are not publicly available. This study uses NHS hospital episode statistics data and was provided within the terms of a data sharing agreement (NIC-393510-D6H1D-v3.2) to the researchers by the Health and Social Care Information Centre (‘NHS Digital’). The data do not belong to the authors and may not be shared by the authors, except in aggregate form for publication. Data can be obtained by submitting a data request through the NHS Digital Data Access Request Service.
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