Background To date, few data on paediatric COVID-19 have been published, and most reports originate from China. This study aimed to capture key data on children and adolescents with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection across Europe to inform physicians and health-care service planning during the ongoing pandemic. Methods This multicentre cohort study involved 82 participating health-care institutions across 25 European countries, using a well established research network-the Paediatric Tuberculosis Network European Trials Group (ptbnet)-that mainly comprises paediatric infectious diseases specialists and paediatric pulmonologists. We included all individuals aged 18 years or younger with confirmed SARS-CoV-2 infection, detected at any anatomical site by RT-PCR, between April 1 and April 24, 2020, during the initial peak of the European COVID-19 pandemic. We explored factors associated with need for intensive care unit (ICU) admission and initiation of drug treatment for COVID-19 using univariable analysis, and applied multivariable logistic regression with backwards stepwise analysis to further explore those factors significantly associated with ICU admission. Findings 582 individuals with PCR-confirmed SARS-CoV-2 infection were included, with a median age of 5•0 years (IQR 0•5-12•0) and a sex ratio of 1•15 males per female. 145 (25%) had pre-existing medical conditions. 363 (62%) individuals were admitted to hospital. 48 (8%) individuals required ICU admission, 25 (4%) mechanical ventilation (median duration 7 days, IQR 2-11, range 1-34), 19 (3%) inotropic support, and one (<1%) extracorporeal membrane oxygenation. Significant risk factors for requiring ICU admission in multivariable analyses were being younger than 1 month (odds ratio 5•06, 95% CI 1•72-14•87; p=0•0035), male sex (2•12, 1•06-4•21; p=0•033), pre-existing medical conditions (3•27, 1•67-6•42; p=0•0015), and presence of lower respiratory tract infection signs or symptoms at presentation (10•46, 5•16-21•23; p<0•0001). The most frequently used drug with antiviral activity was hydroxychloroquine (40 [7%] patients), followed by remdesivir (17 [3%] patients), lopinavir-ritonavir (six [1%] patients), and oseltamivir (three [1%] patients). Immunomodulatory medication used included corticosteroids (22 [4%] patients), intravenous immunoglobulin (seven [1%] patients), tocilizumab (four [1%] patients), anakinra (three [1%] patients), and siltuximab (one [<1%] patient). Four children died (case-fatality rate 0•69%, 95% CI 0•20-1•82); at study end, the remaining 578 were alive and only 25 (4%) were still symptomatic or requiring respiratory support. Interpretation COVID-19 is generally a mild disease in children, including infants. However, a small proportion develop severe disease requiring ICU admission and prolonged ventilation, although fatal outcome is overall rare. The data also reflect the current uncertainties regarding specific treatment options, highlighting that additional data on antiviral and immunomodulatory drugs...

A recent large cohort of 1733 patients from Wuhan found persistent symptoms in 76% of patients 6 months after initial diagnosis. 2 To date, data on Long COVID in children are scarce, with the exception of an earlier description of five children with Long COVID in Sweden. 3 We assessed persistent symptoms in paediatric patients previously diagnosed with COVID-19. | ME THODSThis 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).

ImportanceSome individuals experience persistent symptoms after initial symptomatic SARS-CoV-2 infection (often referred to as Long COVID).ObjectiveTo estimate the proportion of males and females with COVID-19, younger or older than 20 years of age, who had Long COVID symptoms in 2020 and 2021 and their Long COVID symptom duration.Design, Setting, and ParticipantsBayesian meta-regression and pooling of 54 studies and 2 medical record databases with data for 1.2 million individuals (from 22 countries) who had symptomatic SARS-CoV-2 infection. Of the 54 studies, 44 were published and 10 were collaborating cohorts (conducted in Austria, the Faroe Islands, Germany, Iran, Italy, the Netherlands, Russia, Sweden, Switzerland, and the US). The participant data were derived from the 44 published studies (10 501 hospitalized individuals and 42 891 nonhospitalized individuals), the 10 collaborating cohort studies (10 526 and 1906), and the 2 US electronic medical record databases (250 928 and 846 046). Data collection spanned March 2020 to January 2022.ExposuresSymptomatic SARS-CoV-2 infection.Main Outcomes and MeasuresProportion of individuals with at least 1 of the 3 self-reported Long COVID symptom clusters (persistent fatigue with bodily pain or mood swings; cognitive problems; or ongoing respiratory problems) 3 months after SARS-CoV-2 infection in 2020 and 2021, estimated separately for hospitalized and nonhospitalized individuals aged 20 years or older by sex and for both sexes of nonhospitalized individuals younger than 20 years of age.ResultsA total of 1.2 million individuals who had symptomatic SARS-CoV-2 infection were included (mean age, 4-66 years; males, 26%-88%). In the modeled estimates, 6.2% (95% uncertainty interval [UI], 2.4%-13.3%) of individuals who had symptomatic SARS-CoV-2 infection experienced at least 1 of the 3 Long COVID symptom clusters in 2020 and 2021, including 3.2% (95% UI, 0.6%-10.0%) for persistent fatigue with bodily pain or mood swings, 3.7% (95% UI, 0.9%-9.6%) for ongoing respiratory problems, and 2.2% (95% UI, 0.3%-7.6%) for cognitive problems after adjusting for health status before COVID-19, comprising an estimated 51.0% (95% UI, 16.9%-92.4%), 60.4% (95% UI, 18.9%-89.1%), and 35.4% (95% UI, 9.4%-75.1%), respectively, of Long COVID cases. The Long COVID symptom clusters were more common in women aged 20 years or older (10.6% [95% UI, 4.3%-22.2%]) 3 months after symptomatic SARS-CoV-2 infection than in men aged 20 years or older (5.4% [95% UI, 2.2%-11.7%]). Both sexes younger than 20 years of age were estimated to be affected in 2.8% (95% UI, 0.9%-7.0%) of symptomatic SARS-CoV-2 infections. The estimated mean Long COVID symptom cluster duration was 9.0 months (95% UI, 7.0-12.0 months) among hospitalized individuals and 4.0 months (95% UI, 3.6-4.6 months) among nonhospitalized individuals. Among individuals with Long COVID symptoms 3 months after symptomatic SARS-CoV-2 infection, an estimated 15.1% (95% UI, 10.3%-21.1%) continued to experience symptoms at 12 months.Conclusions and RelevanceThis study presents modeled estimates of the proportion of individuals with at least 1 of 3 self-reported Long COVID symptom clusters (persistent fatigue with bodily pain or mood swings; cognitive problems; or ongoing respiratory problems) 3 months after symptomatic SARS-CoV-2 infection.

Human newborns are susceptible to microbial infection related to incompletely defined aspects of the neonatal immune system. To characterize neonatal innate immunity, we studied production of two early response cytokines in response to Toll-like receptor (TLR)-activating microbial stimuli in vitro: the proinflammatory cytokine tumor necrosis factor (TNF)-␣ and IL-6, a multifunctional cytokine with antiinflammatory and Th2-polarizing properties. Neonatal cord blood responses to multiple TLR agonists, including poly dI:dC (TLR3), lipopolysaccharide (LPS) (TLR4), flagellin (TLR5), and CpG DNA (TLR9), are characterized by a higher IL-6/TNF-␣ ratio than in adult peripheral blood. Robust LPS-induced IL-6 production is due to both neonatal cellular (monocyte-) and humoral (serum-) factors. Remarkably, serum collected from newborns during the first week of life demonstrates higher IL-6/TNF-␣ ratios than does cord blood, associated with elevations of the IL-6-inducible acute phase reactants CRP and LPS-binding protein in the first days of life. A high ratio of stimulus-induced IL-6/TNF-␣ production is likely to profoundly modulate both innate and adaptive immune responses in the human newborn.