2. METHODS

This cross‐sectional study included all children≤ 18 year old diagnosed with microbiologically confirmed (PCR analysis on nasopharyngeal swab) COVID‐19 (through a nasopharyngeal swab from March 2020 to October 2020) in Fondazione Policlinico Universitario A. Gemelli IRCCS (Rome, Italy). Only children with a SARS‐CoV‐2 infection diagnosed 30 days before the assessment were included. Patients> 18 years old or with severe neurocognitive disability were excluded, since this would have not allowed a proper assessment of signs and symptoms included in the survey. Caregivers were interviewed about their child's health using a questionnaire (Appendix S1) developed by the Long COVID ISARIC study group, 4 for evaluation of persisting symptoms. Participants were interviewed by two paediatricians, either by phone or in the outpatient department, from 1 September 2020 to 1 January 2021. For those assessed in the outpatient settings, the same survey was used and symptoms reported were collected even if not present at the moment of the visit (eg tachycardia). Also, investigations were not performed at the moment of the assessment, in order to rule‐out other causes, although the survey has a section to ask whether other possible causes have been detected in the meantime. Participants were categorised into groups according to symptoms status during the acute phase (symptomatic/asymptomatic), need for hospitalisation and time from COVID‐19 diagnosis to follow‐up evaluation (< 60, 60–120,> 120 days). Numerical variables were compared using t test or ANOVA and categorical variables with chi‐square or Fisher's exact test where appropriate. All analyses were performed using R version 4.0. 3 (R Foundation). This study was approved by the Institutional Ethic Committee of the Fondazione Policlinico Universitario A. Gemelli IRCCS—Università Cattolica del Sacro Cuore (ID 3777), and all participants consented to participate.

3. RESULTS

One hundred and twenty‐nine children diagnosed with COVID‐19 between March and November 2020 were enrolled (mean age of 11±4.4 years, 62 (48.1%) female). Six children with severe neurocognitive impairment were excluded due to impossibility to report signs/symptoms included in the survey. Hundred and nine children (84.5%) were interviewed by phone call, and the remaining during outpatient assessment. During the acute COVID‐19, 33 children (25.6%) were asymptomatic, and 96 (74.4%) had symptoms. Overall, 6 (4.7%) children were hospitalised, and 3 (2.3%) needed paediatric intensive care unit admission. After the initial diagnosis of COVID‐19, three developed multisystem inflammatory syndrome (2.3%) and two myocarditis (1.6%). Patients were assessed on average 162.5±113.7 days after COVID‐19 microbiological diagnosis. 41.8% completely recovered, 35.7% had one or two symptoms and 22.5% had three or more (Table S1).