Health inequalities exist globally, but limited data exist on this topic for bacteraemia.

In this study we investigated health inequalities surrounding bacteraemia in England, to identify high-risk population groups and areas of intervention.

We retrospectively analysed English surveillance data between 2018 and 2022 for Escherichia coli, Klebsiella species, Pseudomonas aeruginosa, and both meticillin-sensitive and resistant Staphylococcus aureus (MSSA, MRSA) bacteraemia. Crude incidence rates stratified by index of multiple deprivation and ethnic groups were calculated; age-adjusted rate ratios were estimated using negative binomial regression models.

We identified 342,787 bacteraemia cases. Across all pathogens, as the level of deprivation rose, so did the age-adjusted bacteraemia incidence rate ratio. Compared with residents of the 20% least deprived areas of England, residents of the 20% most deprived areas had a 2.68-fold increased bacteraemia rate for MRSA (95% CI: 2.29–3.13) and 1.95-fold for E. coli (95% CI: 1.84–2.05), and 15% higher odds of dying within 30 days of any bacteraemia (95% CI: 1.13–1.19). After age adjustment, the incidence of all bacteraemia was higher in the Asian and Black groups compared with the White group: for MRSA, 79% higher in the Asian (95% CI: 1.51–2.10) and 59% higher in the Black (95% CI: 1.29–1.95) groups. The exception was MSSA, whose incidence was highest in the White group.

Disproportionately higher age-adjusted incidence of bacteraemia occurred in deprived areas and ethnic minorities. These disparities are likely multifactorial, possibly including socioeconomic, cultural, and systemic risk factors and different burden of comorbidities. Better understanding these factors can enable targeted interventions.

Laboratory surveillance detected an unprecedented increase in Cryptosporidium spp. (predominantly Cryptosporidium hominis) in England and Wales in August 2023. Cases are not routinely followed up in all of England and Wales, and initial investigations identified no common exposures.

To perform a retrospective case–case study investigation of the increase in Cryptosporidium spp. in England and Wales.

We conducted an unmatched case–case study with 203 cases of laboratory-confirmed C. hominis and 614 comparator cases of laboratory-confirmed Campylobacter spp. reported between 14 August and 30 September 2023. We fitted a multilevel logistic regression model, with random intercepts for geographical region, to estimate adjusted odds ratios (aOR) for exposures. We present the final model as aOR and 95% confidence intervals (CI).

Multivariable analysis identified associations with swimming pool use (aOR: 5.3, 95% CI: 2.3–9.3), travel to Spain (aOR: 6.5, 95% CI: 3.5–12.3) and young age, with children 0–4 years having the strongest association of being a case (aOR: 3.6, 95% CI: 1.5–8.6). We also identified associations with swimming in a river, and travel to France or Türkiye, but there was low frequency of exposure among cases and comparator cases.

Following the largest recorded increase of Cryptosporidium spp. and in particular C. hominis cases in England and Wales, we identified several exposures, suggesting that causation was likely to be multifactorial. We recommend development of a standardised questionnaire to enable rapid investigation of future case increases, which will improve existing surveillance and inform public health actions.