From the original SARS-CoV-2 strain to the Omicron variant: Predictors of COVID-19 in ambulatory symptomatic children.

OBJECTIVES: To determine the predictors of a positive SARS-CoV-2 test in a pediatric ambulatory setting. PATIENTS AND METHODS: We performed a cross-sectional prospective study (November 2020-February 2022) of 93 ambulatory settings in France. We included symptomatic children < 15 years old tested for SARS-CoV-2. For each period corresponding to the spread of the original strain and its variants (period 1: original strain; period 2: Alpha, period 3: Delta; period 4: Omicron), we used a multivariate analysis to estimate adjusted odds ratios (aORs) associated with COVID-19 among age, signs, symptoms or contact, and 95 % confidence intervals (95CIs). RESULTS: Of 5,336 children, 13.9 % (95CI 13.0-14.8) had a positive test. During the first three periods, the positivity rate ranged from 5.6 % (95CI 4.6-6.7) to 12.6 % (95CI 10.8-14.6). The main factors associated with a positive test were contact with an infected adult at home or outside the home (aOR 11.5 [95CI 4.9-26.9] to 38.9 [95CI 19.3-78.7]) or an infected household child (aOR 15.0 [95CI 4.8-47.1] to 28.4 [95CI 8.7-92.6]). By contrast, during period 4, aORs for these predictors were substantially lower (2.3 [95CI 1.1-4.5] to 5.5 [95CI 3.2-7.7]), but the positivity rate was 45.7 % (95CI 42.3-49.2). CONCLUSIONS: In pediatric ambulatory settings, before the Omicron period, the main predictor of a positive test was contact with an infected person. During the Omicron period, the odds of these predictors were substantially lower while the positivity rate was higher. An accurate diagnostic strategy should only rely on testing and not on age, signs, symptoms or contact.

Decline in pediatric viral and virus-induced infections during lockdown in 2020

Background: The COVID-19 pandemic had led to several national lockdown in France such as many other countries. We hypothesized that these measures would be associated with a decrease in pediatric viral and virus-induced infections that usually disseminate through social contacts. Methods: We conducted a study based on a multicenter prospective French surveillance database, which include all the pediatric emergency department visits of 6 academic hospital located in Paris region from 1st January 2017 to 31st December 2020. The evolution of viral and viralinduced infection such as common cold, bronchiolitis, acute otitis media (AOM), and acute asthma exacerbation were investigated. Urinary tract infections, which are not reported to be correlated with contacts in children, were used as a negative control outcome. Results: A total of 908 887 visits were included. We found a decrease in bronchiolitis, common cold, AOM, and acute asthma exacerbation during first (March-June 2020) and second (November 2020) lockdown, even when school remain open, compared to the three previous years. The annual seasonal bronchiolitis outbreak caused by the respiratory syncytial virus was not observed in 2020 in France. The social distancing and the national mandatory facial mask associated with the curfew seemed to had an effect on transmission of viruses other than SARS-CoV-2. By contrast, urinary tract infections were not impacted by lockdowns. Conclusions: The low rates of bronchiolitis, common cold, AOM, and acute asthma exacerbation found in our study suggest low respiratory virus transmissions in children in France during lockdown. Copyright © 2021 John Libbey Eurotext. Contexte : La lutte contre la pandémie de COVID-19 a conduit de nombreux pays, dont la France, à mettre en place des mesures de confinement. Nous avons émis l'hypothèse que ces mesures seraient associées à une diminution des infections virales et viro-induites pédiatriques qui se propagent généralement par le biais de contacts sociaux. Méthodes : Nous avons mené une étude à partir d'une base de données de surveillance prospective multicentrique française, qui comprend l'ensemble des visites aux urgences pédiatriques de 6 hôpitaux universitaires situés en région parisienne du 1er janvier 2017 au 31 décembre 2020. L'évolution des infections virales et d'origine virale tels que les rhumes, les bronchiolites, les otites moyennes aiguës (OMA) et les crises d'asthme a été étudiée. Les infections urinaires, qui ne sont pas favorisées par les contacts sociaux, ont été utilisées comme comparateurs. Résultats : Au total, 908 887 visites ont été incluses. Nous avons observé, par rapport aux trois années précédentes, une diminution des bronchiolites, des rhumes, des OMA et des crises d'asthme pendant le premier (mars-juin 2020) et le second (novembre 2020) confinement, même lorsque l'école est restée ouverte. L'épidémie annuelle de bronchiolite saisonnière causée par le virus respiratoire syncytial n'a pas été observée en 2020 en France. La distanciation sociale et l'usage obligatoire du masque associé au couvre-feu semblent avoir eu un effet sur la transmission de virus autres que le SARS-CoV-2. Par comparaison, les infections urinaires ne semblent pas avoir été affectées par les confinements. Conclusions : Les faibles taux de bronchiolites, de rhumes, d'OMA et de crises d'asthme observés dans notre étude suggèrent de faibles transmissions de virus respiratoires chez les enfants en France pendant les confinements. Copyright © 2021 John Libbey Eurotext. © 2021 John Libbey Eurotext. All rights reserved.