National outbreak of pertussis in England (2023-2024) in the context of international resurgence.

Abstract

To describe the epidemiology of a large, national outbreak of pertussis in England in 2023-2024, and key control measures implemented. Analysis of data for 2023-24 from multiple public health surveillance systems. England -national surveillance. All age groups but focusing on children and young people up to age 14 years. Laboratory-confirmed cases in the community, deaths and pertussis-related hospital admissions. National control measures implemented as part of outbreak response. 15 750 laboratory confirmed cases were reported in 2023-24, including 989 infants. Of 481 infants under 3 months, 12 died, of whom nine (75%) were born to mothers who were not vaccinated within the recommended timeframe in pregnancy. Incidence rates were highest among infants aged under 3 months. Most hospitalised pertussis cases were infants, but proportionately more hospitalisations in 2024 occurred in older age groups than expected based on earlier years. Whole genome sequencing indicated multiple lineages drove the increase. One isolate from 2023 and one from 2024 possessed 23s ribosomal RNA genotypes associated with macrolide resistance and this was confirmed phenotypically. Multiple control measures were implemented, including revisions to public health guidance and mobilisation work to promote childhood and prenatal vaccination uptake. Following a period of very low incidence during the COVID-19 pandemic, there was a large and rapid rise in pertussis cases across all age groups and geographies in England in 2023-24. Continued, high-quality surveillance and characterisation of circulating pertussis strains will be crucial to understanding evolving disease epidemiology postpandemic.