PEGASUS: Paediatric European Group A Streptococcal United Study.

Introduction Since 2022 there are reports of a rapid increase in invasive group A streptococcal infections (iGAS) in children in some but not all European countries. Detailed information on this increase is lacking. Furthermore, an increase in other invasive infections as well as the emergence of novel pathogens and disease entities is seen, such as MIS-C and severe hepatitis of unknown origin.

Aims To set up a European research network and describe the incidence, risk factors, clinical phenotypes, microbiology and resistance, treatment, and outcomes of iGAS in children across Europe. The network will subsequently be utilized for early alerting regarding the rise of other invasive and emerging infections in children. It will enable swift data collection pertaining to patient characteristics, presentation, progression, and treatment.

Methods International, retrospective cohort and observational surveillance study of children 0-18y attending the ED or admitted to the hospital with iGAS. Clinical and microbiological data, national vaccination schedules, and COVID non-pharmaceutical interventions (NPIs) will be collected and compared between countries. Subsequently, the network will be employed to raise alarms regarding the surge of other invasive infections or emerging infections in children. Anonymous data about these novel infections will be collected, similar to the data from iGAS (clinical characteristics and microbiological data). The study is a non-profit study.

Significance Our study will describe variation in the clinical phenotypes of iGAS, will aid in the understanding of its association with COVID NPIs and allow for comparison between countries. Furthermore, it will aid in early recognition of invasive and emergent infectious diseases in children and the reduction of outbreaks.