Pulmonary Sequelae of Severe Acute COVID-19 and Multisystem Inflammatory Syndrome (MIS-C) in Dutch Children

Background: Although rare, COVID-19 in children may lead to hospitalization due to severe respiratory symptoms, or a hyperinflammatory state called Multisystem Inflammatory Syndrome in Children (MIS-C). This study examined respiratory morbidity in children 5 to 12 months after hospitalization for MIS-C or COVID-19. Methods: In this multi-center, prospective cohort study, children (0–17 years) with a history of hospitalization for MIS-C or COVID-19 in Dutch hospitals were invited for follow-up. Visits were scheduled in one of three academic hospitals, to evaluate current clinical status and health-related quality of life (HRQoL), and perform lung function tests and cardiopulmonary exercise testing (CPET). Results: 72 children were included (43 MIS-C, 29 COVID-19), of whom 19% (5% and 41%, respectively) reported long-term respiratory symptoms including dyspnea and cough, a median of 8 months after hospitalization. Fatigue was the most common non-respiratory symptom. HRQoL was more frequently (60%) impaired in the COVID-19 group than the MIS-C group (14%). Spirometry (n = 48) and CPET (n = 40) were conducted in children aged > 4 and > 6 years, respectively. Spirometry was abnormal in 15% of the MIS-C group and 44% of COVID-19 group, CPET in 41% and 75%, respectively. Deconditioning patterns were the most common reason (30%) for abnormal CPET results. Conclusion: Long-term respiratory sequelae and fatigue occurred after both MIS-C and severe COVID-19, but respiratory symptoms and impaired HRQoL were more frequent after COVID-19. Lung function and CPET abnormalities in children with COVID-19 often corresponded with symptoms. Children with MIS-C often showed CPET abnormalities without respiratory complaints or lung function changes.