Prevalence and risk factors of post-coronavirus disease 2019 condition among children and adolescents in Japan: A matched case-control study in the general population

ObjectivesTo examine prevalence and risk factors for post-COVID-19 condition (PCC) in a paediatric population.MethodsThe study included patients aged 5–17 years with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection between 1 March 2021 and 30 April 2022 and matched non-infected controls from Yao City, Japan. We compared parent-reported symptoms persisting ≥2 months (present at 3 months post-infection for patients) between the groups. COVID-19 vaccination data was obtained from the Vaccination Registry.ResultsAmong 8,167 invited individuals, 3,141 (1,800 cases, mean age: 10.4 years, 46.1% females; 1,341 controls, mean age 10.5 years, 47.1% females) participated. Patients had elapsed average 273 (185–605) days from infection, and 1,708 (94.9%) experienced mild acute symptoms. Patients had higher odds of having persistent symptoms than did controls (6.3% vs 2.2%, adjusted odds ratio [aOR]: 3.15, 95% confidence interval: 2.08–4.77), with 53.6% of them reporting current disruption due to the symptoms. Older age, low household income, pre-existing allergy, and autonomic nervous system disease were associated with increased risks of developing PCC; two prior vaccination doses reduced these risks (aOR: 0.52, 0.29–0.93).ConclusionsSARS-CoV-2 infection, including omicron infections heighten persistent symptom risk in the paediatric population, necessitating preventive strategies, notably vaccination.