not-yet-known not-yet-known not-yet-known unknown Objective: To investigate the prevalence of clinical manifestations of post COVID-19 condition, also known as long COVID, in children hospitalized with COVID-19. Methods: This is a systematic review of observational studies. We conducted the search on the databases of PUBMED and EMBASE (up to March 15, 2023). We used the following search strategy: ”long COVID” OR ”post COVID-19” OR ”post-acute 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 the clinical manifestations of post COVID-19 condition in children (<18 years) admitted with COVID-19. We used the WHO case definition of post COVID-19 condition (ICD-10 U09). Four authors independently assessed the studies. We performed the meta-analysis of prevalence using a random-effects model. Results: 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%), followed by nonspecific respiratory symptoms (12%, 95% CI: 0-48%) and nonspecific gastrointestinal symptoms (10%, 95% CI: 0-37%). In the period ≥12 months after the initial infection, the pooled prevalence of post COVID symptoms was lower, with 6% (95% CI: 2-10%) for exercise intolerance and 3% (95% CI: 0-8%) for fatigue. Conclusions: Clinical manifestations of post COVID condition in hospitalized children include symptoms across multiple organ systems, with higher prevalence in the period up to 12 months after the acute phase of COVID-19.

Management of acute bronchiolitis remains controversial due to lack of strong evidence-based data. Nebulized epinephrine and hypertonic saline have been studied in infants with bronchiolitis, with conflicting results. This systematic review and meta-analysis aimed to evaluate the efficacy on length of stay (LOS), clinical severity scores (CSS), oxygen saturation (SaO2) and safety profile of nebulized epinephrine plus hypertonic saline (HS) in infants with acute bronchiolitis. Outcomes were represented by mean differences (MD) or standard mean differences (SMD) and 95% confidence intervals (CIs) were utilized. 18 trials were systematically selected and 16 of them contributed for the meta-analysis (1,756 patients). Overall, a modest but significant positive impact was observed of the combination therapy on LOS (MD of – 0.35 days, 95% CI -0.62 to -0.08, p = 0.01, I2 = 91%). Stratification by time of CSS assessment unveiled positive results in favor of the combination therapy in CSS assessed 48 hours and 72 hours after the admission (SMD of -0.35, 95% CI -0.62 to -0.09, p = 0.008, I2 = 41% and SMD of -0.27, 95% CI -0.50 to -0.04, p = 0.02, I2 = 0%, respectively). No difference in SaO2 was observed. Additional data showed a consistent safety profile, with a low rate of adverse events (1%), most of them mild and transient. In conclusion, nebulized epinephrine plus HS may be considered as a safe, cheap and efficient alternative for decreasing LOS and CSS in infants with acute bronchiolitis, especially on those who require more than 48 hours of hospitalization.