http://www.sudoc.fr/263054454 fr FR Thèse d’exercice La COVID-19 en pédiatrie en Alsace : prévalence de l'infection à SARS-coV2 et étude de la réponse humorale dans la population pédiatrique/thèse présentée pour le diplôme d'État de docteur en médecine, diplôme d'État, mention Biologie Médica Faculté de médecine, maïeutique et sciences de la santé 2022-06-30 Pédiatrie 618.92 Biry Morgane Covid-19 SARS-CoV-2 (virus) Alsace (France) application/pdf Accès libre https://publication-theses.unistra.fr/public/theses_exercice/MED/2022/2022_BIRY_Morgane.pdf Médecine (biologie médicale) Objectives : the Grand Est region was one of the most affected in France by the first wave of the COVID-19 pandemic. The main objective of this retrospective and monocentric study was to determine the prevalence of SARS-CoV-2 infection among children screened at the HUS Virology laboratory by periscope (N1: 18 months - 5 years) and school age group (N2: 6 - 10 years and N3: 11 - 16 years), both in the pre-pandemic period and throughout the first pandemic wave. The aim was also to characterize the spectrum of the disease in COVID patients in the pediatric population, from a clinical point of view but also from a virological and serological point of view. Finally, this work was interested in the modalities of intra-familial transmission of the infection. Patients and methods: In the pre-pandemic period, sera from children collected between 30/12/2019 and 31/03/2020 for viral serology were tested with the following kits: Biosynex COVID-19 BSS (IgM and IgG anti-RBD protein Spike (S)), Abbott Architect (IgG anti-nucleocapsid), Euroimmun (IgA and IgG anti-S1 protein S). Positive sera from children with a compatible clinical history were tested by seroneutralization using virus pseudoparticles (wild-type strain). From 01/03/20 to 11/05/20, SARS-CoV-2 RT-PCR screening was performed using the Institut Pasteur IP2 and IP4 technique (RdRp gene). Serologies were performed using the following kits: Abbott Architect (IgG anti-S Quant II), Euroimmun (IgA and IgG anti-S1). From 12/05 to 31/10/20, SARS-CoV-2 RT-PCR screening was performed using the IP2 and IP4 technique or a kit marketed by BGI (ORF1ab). Results: In the pre-pandemic period, 75 children, equally distributed among the three age groups and by sex, were tested. The median time from sampling to the date of onset of symptoms was 6 days. Eleven patients (14.7%) tested positive for anti-S IgA and/or IgG. Two children sampled between 08/01 and 16/01, had suggestive symptoms, very high IgA indexes (-20 S/Co), and neutralizing antibodies to wild-type virus (2.0 and 2.9 log IC50). From 01/03 to 11/05/20: 519 children were tested by RT-PCR, of whom 26 (5%) were positive. Patients aged 11 to - 0.05). 65.7% of positive pediatric cases were diagnosed before school closure and national containment. Data from 11 households were analyzed, showing a statistical association between the positive result of one child and another sibling (p - 0.05). For 91 patients (14 positive and 77 RT-PCR negative), analysis of clinical and exposure data showed that only contact with a confirmed or suspected COVID-19 case was associated with SARS-CoV-2 positivity in children (p - 0.05). 11/71 patients (15.5%) had positive serologies of which only 3 were RT-PCR positive. From 12/05 to 10/31/20: out of 2255 smears performed in 2140 children (N1 = 586, N2 = 629, N3 = 1040), 29 (1.3%) were positive. Patients aged 6 to - 0.05), which is not stronger than that found from the positive result of an adult. The latter are more often affected than children (p - 0.05). Conclusion: This work suggests a circulation of SARS-CoV-2 in our territory since January in children. It underlines the importance of intra-familial transmission in pediatric COVID-19 cases. Pediatric data remain scarce concerning the humoral response in this population for which the concern of vaccination arises, between the benefit/risk balance at the individual and collective levels. These d'exercice Unistra