The COVID-19 pandemic in children and young people during 2022–24: what new did we learn?

The research conducted between 2022 and 2024 has advanced our understanding of COVID-19 in children and young people (CYP), particularly with the emergence of the Omicron variant and its subvariants. The findings have reinforced that, while Omicron infections are often milder compared to earlier variants, the overall seroprevalence of SARS-CoV-2 in children has increased, with notable regional and demographic disparities. COVID-19-related hospitalisation rates in children rose during Omicron waves, especially among infants, unvaccinated individuals, and CYP at higher risk, i.e. with comorbidities such as obesity, diabetes, and neurological or cardiac conditions. Despite this, severe disease and mortality in children remained very low. The observed increases in type 1 diabetes incidence and multisystem inflammatory syndrome in children (MIS-C) have also highlighted the broader systemic effects of SARS-CoV-2 in paediatric populations. Evidence has underscored the protective effect of vaccination in preventing severe disease and MIS-C and vaccine safety, emphasising the need for targeted immunisation strategies, particularly among children who may be at higher risk. Studies have also estimated that a significant proportion of children experienced persistent post-COVID-19 infection symptoms such as fatigue, mood disturbances, sleep disorders, and respiratory difficulties, but the reported prevalence varied widely, from as low as 1.6% to as high as 70%, due to differences in study methodologies, case definitions, and populations studied. Standardised definitions and measurement tools, such as those developed through international consensus processes, are required to improve diagnosis, treatment, and research into this persisting condition. Ethnic disparities in vaccine uptake persist, implying that vaccine hesitancy and accessibility, alongside approaches to countering disinformation, are important areas for future research.