Substantial Reduction in Pneumococcal Haemolytic Uraemic Syndrome After Vaccine Replacement

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Pneumococcal haemolytic uraemic syndrome (pHUS) is an uncommon but serious complication of invasive pneumococcal disease in children.
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Sweden recorded an approximately 10-fold rise in pHUS incidence after replacing PCV13 with PCV10 in 2019, alongside the emergence of serotypes 3 and 19A.
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After Sweden introduced PCV15, which includes serotypes 3 and 19A, surveillance identified no pHUS cases in 2025, an incidence of 0 per 100,000 children.
4

Paediatric invasive pneumococcal disease also declined after PCV15 introduction, whereas adults experienced no similar reduction.
5

The ecological findings cannot establish causality, and continued national surveillance is needed to determine whether the absence of pHUS cases persists.

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