text: Similar patterns of sup 18 sup F FDG brain PET hypometabolism in paediatric and adult patients with long COVID a paediatric case series Several weeks after COVID 19 infection some children report the persistence or recurrence of functional complaints This clinical presentation has been referred as long COVID in the adult population and an sup 18 sup F FDG brain PET hypometabolic pattern has recently been suggested as a biomarker Herein we present a retrospective analysis of 7 paediatric patients with suspected long COVID who were explored by sup 18 sup F FDG brain PET exam Metabolic brain findings were confronted to those obtained in adult patients with long COVID in comparison to their respective age matched control groups Review of clinical examination and whole brain voxel based analysis of sup 18 sup F FDG PET metabolism of the 7 children in comparison to 21 paediatric controls 35 adult patients with long COVID and 44 healthy adult subjects Despite lower initial severity at the acute stage of the infection paediatric patients demonstrated on average 5 months later a similar brain hypometabolic pattern as that found in adult long COVID patients involving bilateral medial temporal lobes brainstem and cerebellum p voxel 0 001 p cluster 0 05 FWE corrected and also the right olfactory gyrus after small volume correction p voxel 0 010 FWE corrected with partial PET recovery in two children at follow up These results provide arguments in favour of possible long COVID in children with a similar functional brain involvement to those found in adults regardless of age and initial severity 