Impact of vaccination on pertussis-related hospital admissions in children in Scotland from January 2013 to July 2024: a cohort study.

BACKGROUNDIn Scotland, the number of pertussis infections recorded in children in 2024 was the highest of any year in the last decade. The protective role of vaccination against severe infection and associated hospitalisations has not been assessed.AIMTo investigate the effect of vaccination and sociodemographic factors on pertussis-related hospitalisations in Scottish children aged under 18 years.METHODSIn a retrospective cohort study, laboratory-confirmed pertussis cases from January 2013 to July 2024 were extracted from the national electronic surveillance system and linked to hospitalisation data from Scottish Morbidity Records and vaccination data from the national immunisations database. The outcome was a pertussis-associated hospitalisation. Multivariable logistic regression was used to calculate odds ratios (OR) for the association between vaccination status and hospitalisation, adjusted for age, sex, ethnicity and deprivation status.RESULTSThere were 3,982 laboratory-confirmed cases of pertussis during the study period. Children fully vaccinated for age had significantly lower odds of hospitalisations than unvaccinated children (adjusted OR (aOR): 0.31; 95% CI: 0.21-0.46). Being partially vaccinated for age did not significantly reduce hospitalisations relative to unvaccinated children (aOR: 0.80; 95% CI: 0.47-1.33). In the univariable analysis, children living in the most deprived areas had significantly more hospitalisations than those in the least deprived areas (OR: 3.90; 95% CI: 2.41-6.56). This association was not significant when adjusted for the effect of vaccination (aOR: 1.47; 95% CI: 0.84-2.66).CONCLUSIONSFully vaccinated children had significantly lower odds of hospitalisation, indicative of less severe disease. This emphasises the importance of fully vaccinating children according to the childhood immunisation schedule.