Prevalence of symptoms of post-COVID-19 condition (long COVID) in children hospitalized with COVID-19: A systematic review of observational studies.

This systematic review aimed to investigate the prevalence of symptoms of post-COVID-19 condition (long COVID), in children hospitalized with COVID-19. We searched PUBMED and EMBASE on 15 March, 2023, using search strategy: "long COVID" OR "post-COVID-19" OR "postacute COVID-19" OR "long-term COVID" OR "COVID-19 sequelae" OR "persistent COVID-19" OR "chronic COVID-19". We included observational studies (case-control, cross-sectional, cohort, or case series) that investigated symptoms of post-COVID-19 condition (long COVID) in children (<18 years) admitted with COVID-19. We used the WHO case definition of post-COVID-19 condition. Long COVID was defined as persistence of otherwise unexplained symptoms for at least three months after SARS-CoV-2 infection. We used the command "metaprop" to perform random-effects meta-analysis. Eleven studies involving 2279 patients were included. In the period between ≥3 months and <12 months after acute COVID-19, the most frequent symptom was exercise intolerance with a pooled prevalence of 29% (95% CI: 7%-57%, I = 95%), followed by nonspecific respiratory symptoms (12%, 95% CI: 0%-48%, I = 0%), psychological disorders (10%, 95% CI: 1%-25%, I = 97%), and nonspecific gastrointestinal symptoms (10%, 95% CI: 0%-37%, I = 99%). In the period ≥12 months after the initial infection, the pooled prevalence of post COVID symptoms was lower, with 6% (95% CI: 2%-10%, I = 83%) for exercise intolerance and 3% (95% CI: 0%-8%, I = 89%) for fatigue. In conclusion, symptoms of post-COVID condition (long COVID) in hospitalized children affect multiple organ systems, with higher prevalence in the period up to 12 months after the acute phase of COVID-19.