Streptococcus pneumoniae haemolytic uraemic syndrome in Aotearoa New Zealand across changing pneumococcal conjugate vaccine eras.

Abstract

Objective: To describe the epidemiology, clinical features, microbiology and outcomes of paediatric Streptococcus pneumoniae haemolytic uraemic syndrome (SpHUS) in Aotearoa New Zealand across changing pneumococcal conjugate vaccine (PCV) eras.

Design: Retrospective case series.

Setting: National paediatric tertiary referral centre, New Zealand.

Patients: Children aged 0-15 years with SpHUS between 2008 and 2024.

Main outcome measures: Clinical presentation, microbiology and serotype distribution, acute severity and long-term renal outcomes.

Results: 39 cases were identified; 26/39 (67%) occurred between 2020 and 2024. Median age was 18 months, with 26/39 (67%) aged <2 years. Māori and Pacific children comprised 24/39 (62%) of cases. Complicated pneumonia was the predominant presentation (36/39, 92%). Among 32 cases with serotype data, 27/32 (84%) were serotype 19A, including 21/21 cases from 2020 to 2024. Most children were PCV-immunised (31/39, 79%), with 6/32 (19%) infected with vaccine-covered serotypes. Disease severity was high: 35/39 (90%) required intensive care and 31/39 (79%) required kidney replacement therapy (median 13 days). Mortality was 2/39 (5%) and 2/39 (5%) required kidney transplantation. Among survivors with follow-up, 13/30 (43%) had chronic kidney disease.

Conclusions: SpHUS in New Zealand has increased since 2020, during a period of rising invasive pneumococcal disease, predominantly involving serotype 19A, with high acute severity and substantial long-term kidney morbidity. The burden is disproportionately borne by Māori and Pacific children, highlighting the need for ongoing surveillance and vaccine strategies responsive to local epidemiology.