Shifting tides: increased severity despite fewer visits for infant respiratory infections across two consecutive post-pandemic winters in Northern Italy.

This study compares infant (0-24 months) respiratory infection presentations to a Northern Italian paediatric emergency department across two post-pandemic winters (2022-2023 vs 2023-2024). Despite an approximate 44% reduction in visits in 2023-2024 (N=176 in 2023-2024 vs N=317 in 2022-2023), infants in the 2023-2024 season experienced significantly higher proportions of ventilatory support (51.1% vs 32.8%, p<0.001) and intensive care unit admission (15.9% vs 1.9%, p<0.001) than those presenting in 2022-2023, with a non-significant trend towards higher hospitalisation (88.1% vs 81.7%, p=0.052). Respiratory syncytial virus re-emerged as the dominant pathogen (43.2% vs 27.7%, p<0.001) in 2023-2024, alongside increased human metapneumovirus and influenza A H1N1. These findings highlight a concerning shift towards increased severity, underscoring the need for ongoing surveillance.