Invasive group A streptococcal infections requiring paediatric intensive care in children and adolescents: a nationwide retrospective cohort study in Austria.

Several European countries reported a marked rise in paediatric invasive group A streptococcal (iGAS) infections from mid-2022 onwards. We describe the clinical spectrum and intensive care course of children with iGAS admitted to Austrian paediatric intensive care units (PICUs) during this period. We conducted a nationwide, multicentre, retrospective observational cohort study across all 13 Austrian PICUs. Children aged 0-18 years admitted between 1 September 2022 and 31 March 2024 with microbiologically confirmed iGAS were identified using a standardised, pseudonymised case report form. Data on demographics, clinical presentation, organ support, co-infections, microbiology, and outcomes were collected. All 13 Austrian PICUs participated, contributing 70 cases. The most frequent initial symptoms were pleural empyema (51.4%), pneumonia (45.7%), sepsis (44.3%), and septic-shock (25.7%). Co-infections (viral/bacterial) were documented in 55.7%. Organ support requirements were substantial: 72.9% required mechanical ventilation (44.3% invasive; 28.6% non-invasive), 50.0% received vasoactive therapy, and 14.3% underwent cardiopulmonary resuscitation. Extracorporeal therapies were used in 10.0% overall, including extracorporeal membrane oxygenation and continuous renal replacement therapy. Microbiological confirmation most commonly derived from sterile sites, particularly pleural fluid and blood cultures. Overall mortality was 14.3%.   Conclusion: During the 2022-2024 surge, iGAS presentations requiring PICU admission in Austria were predominantly respiratory, with high rates of organ support and notable mortality. These findings highlight the need for early recognition of respiratory-focused iGAS, careful assessment for co-infections, and timely access to advanced organ support in experienced centers. Prospective surveillance incorporating standardised diagnostics and treatment data is warranted. What is Known: • Since mid-2022, several European countries have reported a resurgence of paediatric invasive group A streptococcal infections (iGAS) with increased disease severity. iGAS can lead to rapid clinical deterioration, frequently requiring intensive care and advanced organ support. What is New: • This nationwide multicentre study describes the full clinical spectrum and intensive care course of paediatric iGAS cases admitted to all Austrian PICUs during the 2022-2024 surge. Respiratory-focused disease predominated, with high rates of mechanical ventilation, vasoactive support, extracorporeal therapies, and a notable mortality..