Invasive Group A Streptococcal Infections Admitted to the Children's Hospital at Westmead-July 2018 to June 2023

Invasive Group A Streptococcal (iGAS) disease, associated with severe clinical outcomes and high morbidity and mortality, resurged globally following suppression during the early COVID-19 pandemic. This retrospective observational study examines the frequency and clinical characteristics of iGAS cases admitted to an Australian tertiary paediatric hospital over 5 years (1 July 2018-30 June 2023).

Data was gathered from electronic medical records of patients diagnosed with iGAS at The Children's Hospital at Westmead (CHW) during the study period. Demographic and clinical characteristics were analysed using Student T, Mann-Whitney U and Chi-squared tests.

During the study, 61 iGAS patients were admitted to CHW. Admissions peaked in late 2018 and 2019 (22/61), declined sharply throughout 2020 and 2021 (5/61), and rose steeply in 2022 and early 2023 (34/61). The most common iGAS isolates were from blood (40%) and pleural fluid (28%), correlating with the most common iGAS diagnoses: pneumonia (41%), empyema (39%) and sepsis (28%). Many patients presented with cough (48%) and coryza (39%), with 63% of tested individuals having viral coinfections. Pre-pandemic cases showed higher peak neutrophil counts (median: 22.8 × 10⁹/L vs. 17.1 × 10⁹/L, p = 0.04) and ICU admission rates (64% vs. 29%, p = 0.011), while other severity indices remained similar.

This study observed an initial decline in iGAS cases during pandemic restrictions, followed by a resurgence post-pandemic with no concurrent increase in severity. Viral coinfections were frequent, which may complicate clinical assessment, emphasising the need for heightened vigilance. The acute severity of iGAS highlights the importance of early recognition and management.