Direct and indirect vaccination effects on SARS-CoV-2 infection in day-care centres: Evaluating the policy for early vaccination of day-care staff in Germany, 2021.

To mitigate the known high transmission risk in day-care facilities for children aged 0-6 years, day-care staff were given priority for SARS-CoV-2 vaccination in Rhineland-Palatinate, Germany, in March 2021. This study assessed direct and indirect effects of early vaccination of day-care staff on SARS-CoV-2 transmission in daycares with the aim to provide a basis for the prioritisation of scarce vaccines in the future. Data came from statutory infectious disease notifications in educational institutions and from in-depth investigations by the district public health authorities. Using interrupted time series analyses, we measured the effect of mRNA-based vaccination of day-care staff on SARS-CoV-2 infections and transmission. Among 566 index cases from day-care centres, the mean number of secondary SARS-CoV-2 infections per index case dropped by -0.60 case per month after March 2021. The proportion of staff among all cases reported from daycares was around 60% in the pre-interruption phase and significantly decreased by 27 percentage points immediately in March 2021 and by further 6 percentage points each month in the post-interruption phase. Early vaccination of day-care staff reduced SARS-CoV-2 cases in the overall day-care setting and thus also protected unvaccinated children. This should inform future decisions on vaccination prioritisation.

Structure of Patients and Outcome of the Triage Process for the Dental Treatment in General Anesthesia

Introduction: Aim of the study was to analyse the structure of patients referred for dental treatment in general anaesthesia (GA) and to analyse the triage outcomes. Material(s) and Method(s): Retrospective chart analysis of patients referred between January 1st 2018 and July 7th 2022 was performed. Following data were registered: age, sex, diagnosis/ reason for referral for GA, indication for dental treatment in GA, trisage outcome and waiting time for the GA procedure. Result(s): Charts of 193 referred in the aforementioned period were analysed. Most common reason for the referral was autism (65/33.7%), cerebral paralysis (29/15%) and mental retardation (27/14%). Indication for dental treatment in GA was found in 156(80.8%) patients while in 37(19.2%) patients no indication for dental treatment in GA was found. Out of the 156 patients who were indicated for dental treatment in GA, 98(62.8%) patients were managed through day-care surgery and 8(5.2%) patients were admitted to hospital. Twenty patients (12.8%) were still waiting for their GA appointment in the time of analysis, 29(18.6%) were lost to follow up and in one (0.6%) patient the anaesthesiologist recommended ambulatory treatment due to increased risk. Out of the 37 patients in whom no indication for the treatment in GA was found, 13(35.2%) had no caries, 16/ (43.2%) were referred to paediatric dentist and 8(21.6%) were managed on the initial exam. Median time of waiting for the procedure was 120(10-365) days. Before the COVID- 19 pandemics median waiting time was 90(15-300) days, and after the COVID-19 pandemics median waiting time was 135(10-365) days. Conclusion(s): In the majority of the patients referred for dental treatment in GA, indication for the procedure was established. Majority of the referred patients can be managed through a day-care surgery. COVID-19 pandemics is probably one of the reasons for the increased GA procedure waiting time.

The Relative Contributions of Center Demographic, Director, Parental, Social, Environmental, and Policy Factors to Changes in Outdoor Play in Childcare Centers During the COVID-19 Pandemic.

BACKGROUND: The primary objective of this study was to investigate the relative contributions of factors from multiple social-ecological levels in explaining outdoor play changes in childcare centers during the COVID-19 pandemic. METHODS: In Alberta, Canada, licensed childcare center directors (n = 160) completed an online questionnaire. For outcomes, changes in the frequency and duration of outdoor play in childcare centers during COVID-19 compared to before COVID-19 were measured. For exposures, center demographic, director, parental, social, environmental, and policy-level factors were measured. Hierarchical regression analyses were conducted separately for winter (December-March) and nonwinter months (April-November). RESULTS: In most instances, factors at each social-ecological level explained a statistically significant amount of unique variance in changes in outdoor play in childcare centers during COVID-19. Full models accounted for more than 26% of the variance in the outcomes. Changes in parental interest in outdoor play was the most consistent correlate of changes in the frequency and duration of outdoor play in both winter and nonwinter months during COVID-19. In terms of changes in the duration of outdoor play, social support from the provincial government, health authority, and licensing, and changes in the number of play areas in licensed outdoor play spaces were also consistent correlates in both winter and nonwinter months during COVID-19. CONCLUSIONS: Factors from multiple social-ecological levels uniquely contributed to changes in outdoor play in childcare centers during the COVID-19 pandemic. Findings can help inform interventions and public health initiatives related to outdoor play in childcare centers during and after the ongoing pandemic.

Prevalence, sociodemographic and household characteristics, and impacts of disrupted child care due to the COVID-19 pandemic in the U.S., April-July 2021.

Child care closures have become pervasive in the U.S. due to the COVID-19 pandemic. Consequently, parents and caregivers' jobs have been affected as they have needed to care for children at home. This study estimated the burden of disrupted child care due to the COVID-19 pandemic and the pandemic's impact on employment among U.S. households between April and July 2021. Data came from the U.S. Census Bureau's Household Pulse Survey, Phase 3.1. The study sample included 55,312 households with any children in a child care arrangement. We estimated the prevalence of disrupted child care overall and by select sociodemographic and household characteristics as well as employment impacts among households that experienced disrupted child care. Overall, 20.4% (95% confidence interval: 19.1, 21.7) of U.S. households experienced disrupted child care; percentages varied by state from a low of 7.7% in Utah to a high of 29.4% in the District of Columbia. The prevalence of disrupted child care was highest among non-Hispanic Asian/Pacific Islander, non-Hispanic Black, low-income, and households that experienced material hardship. Adults were most likely to report supervising children while working, cutting work hours, and taking unpaid leave due to disruptions in child care. Continued support to the child care industry and to families with children may reduce the impacts of disrupted child care.

SARS-CoV-2 viral clearance and viral load kinetics in young children (1-6 years) compared to adults: Results of a longitudinal study in Germany.

Objective: To investigate SARS-COV-2 viral clearance and viral load kinetics in the course of infection in children aged 1-6 years in comparison with adults. Methods: Prospective cohort study of infected daycare children and staff and their close contacts in households from 11/2020 to 06/2021. Adult participants took upper respiratory tract specimen from themselves and/or their children, for PCR tests on SARS-CoV-2. Data on symptoms and exposure were used to determine the date of probable infection for each participant. We determined (a) viral clearance, and (b) viral load dynamics over time. Samples were taken from day 4-6 to day 16-18 after diagnosis of the index case in the respective daycare group (5 samples per participant). Results: We included 40 children (1-6 years) and 67 adults (18-77 years) with SARS-CoV-2 infection. Samples were available at a mean of 4.3 points of time per participant. Among the participants, the 12-day study period fell in different periods within the individual course of infection, ranging from day 5-17 to day 15-26 after assumed infection.Children reached viral clearance at a median of 20 days after assumed infection (95% CI 17-21 days, Kaplan-Meier Analysis), adults at 23 days (95% CI 20-25 days, difference not significant). In both children and adults, viral load decreased over time with trajectories of the mean viral load not being statistically different between groups. Kaplan-Meier calculations show that from day 15 (95% CI 13-15), 50% of all participants had a viral load <1 million copies/ml, i.e. were no longer infectious or negative. Conclusion: Children aged 1-6 and adults infected with SARS-CoV-2 (wild type and Alpha variant) did not differ significantly in terms of viral load kinetics and time needed to clear the virus. Therefore, containment measures are important also in the daycare settings as long as the pandemic continues.

Parents under stress: Evaluating emergency childcare policies during the first COVID-19 lockdown in Germany.

What are the effects of school and daycare facility closures during the COVID-19 pandemic on parental well-being and parenting behavior? Can emergency childcare policies during a pandemic mitigate increases in parental stress and negative parenting behavior? To answer these questions, this study leverages cross-state variation in emergency childcare eligibility rules during the first COVID-19 lockdown in Germany and draws on unique data from the 2019 and 2020 waves of the German AID:A family panel. Employing a triple-differences approach we identify short- to medium-term intention-to-treat effects and find that while emergency care policies did not considerably affect parents' life satisfaction, partnership satisfaction or mental health, they have been effective in diminishing harsh parenting behavior. We find partly gendered effects, specifically on paternal parenting behavior. Our results suggest that decreasing parental well-being likely constitutes a general effect of the pandemic, whereas the observed increase in negative and potentially harmful parenting behavior is largely directly caused by school and daycare facility closures.

Impact of Daycare Service Interruption during COVID-19 Pandemic on Physical and Mental Functions and Nutrition in Older People with Dementia.

This study evaluated changes of cognitive, physical, and nutritional status before and after the interruption and resumption of daycare services during the COVID-19 pandemic in older dementia people in a daycare center. Comprehensive geriatric assessment data were analyzed before and after the lockdown of daycare center services, including mini-mental state examination, activities of daily living (ADL) scores, mini-nutritional assessment-short forms (MNA-SF), and timed up-and-go (TUG) tests. Among 19 dementia people participating in daycare services, 17 participants were enrolled in the study with, finally, two excluded because of incomplete follow-ups. They had a median age of 81 years; their MNA-SF scores and TUG values deteriorated significantly after a 3-month closure of daycare services (p < 0.05), and after resumption of daycare services the MNA-SF scores and TUG values recovered to near the pre-lockdown levels (p < 0.05). Besides, baseline ADL scores predicted a decline and recovery of TUG and MNA-SF values. Our findings suggest that planning continuous support for older dementia adults is important for daycare facilities during COVID-19 pandemic confinement.

Transmission of SARS-CoV-2 among children and staff in German daycare centres.

In daycare centres, the close contact of children with other children and employees favours the transmission of infections. The majority of children <6 years attend daycare programmes in Germany, but the role of daycare centres in the SARS-CoV-2 pandemic is unclear. We investigated the transmission risk in daycare centres and the spread of SARS-CoV-2 to associated households. 30 daycare groups with at least one recent laboratory-confirmed SARS-CoV-2 case were enrolled in the study (10/2020-06/2021). Close contact persons within daycare and households were examined over a 12-day period (repeated SARS-CoV-2 PCR tests, genetic sequencing of viruses, symptom diary). Households were interviewed to gain comprehensive information on each outbreak. We determined primary cases for all daycare groups. The number of secondary cases varied considerably between daycare groups. The pooled secondary attack rate (SAR) across all 30 daycare centres was 9.6%. The SAR tended to be higher when the Alpha variant was detected (15.9% vs. 5.1% with evidence of wild type). The household SAR was 53.3%. Exposed daycare children were less likely to get infected with SARS-CoV-2 than employees (7.7% vs. 15.5%). Containment measures in daycare programmes are critical to reduce SARS-CoV-2 transmission, especially to avoid spread to associated households.

Identifying behavior of long-distance virus transmission and mitigation performance from a COVID-19 outbreak of a daycare center.

During the last two years, hundreds of millions of people in the world have been infected with SARS-CoV-2 due to recurrent waves and closed spaces. Daycare centers are critical infrastructures that cannot be replaced, even during the COVID-19 period. However, the existing settings in daycare centers may pose risks of inevitable close contact between teachers and children, as well as fomite and airborne transmission during care hours. Therefore, reinforced mitigation strategies have been applied in daycare centers to reduce potential indoor virus transfer in many countries. However, numerous outbreaks of COVID-19 have been reported in daycare centers. Therefore, in this study, researchers focused on the risk and behavior of long-distance virus transmission based on the detected viruses on air purifier filter sampling in a daycare center outbreak in Korea. Various experiments of possible situations were conducted in nursing rooms based on field interviews. The experiments monitored the long-distance transmission behavior of aerosol-sized particles and visualized particle behavior at the daycare center. The results of this study revealed that long-distance virus transmission is possible under the current settings in the daycare center, and flush-out can be an important countermeasure with reinforced ventilation methods to prevent potential airborne spread in the daycare center. The results of air purifiers represented that air purifiers should be properly installed and operated in the daycare center to prevent airborne virus spread by airflow during occupied hours. The findings of this study will contribute to the understanding of airborne virus risk and the development of customized virus measures for daycare centers.

Assessment of ANN Algorithms for the Concentration Prediction of Indoor Air Pollutants in Child Daycare Centers

As the time spent by people indoors continues to significantly increase, much attention has been paid to indoor air quality. While many IAQ studies have been conducted through field measurements, the use of data-driven techniques such as machine learning has been increasingly used for the prediction of indoor air pollutants. For the present study, the concentrations of indoor air pollutants such as CO2, PM2.5, and VOCs in child daycare centers were predicted by using an artificial neural network model with three different training algorithms including Levenberg–Marquardt, Bayesian regularization, and Broyden–Fletcher–Goldfarb–Shanno quasi-Newton methods. For training and validation, data of indoor pollutants measured in child daycare facilities over a 1-month period were used. The results showed all the models produced a good performance for the prediction of indoor pollutants compared with the measured data. Among the models, the prediction by the LM model met the acceptable criteria of ASHRAE guideline 14 under all conditions. It was observed that the prediction performance decreased as the number of hidden layers increased. Moreover, the prediction performance was differed by the type of indoor pollutant. This was caused by patterns observed in the measured data. Considering the outcomes of the study, better prediction results can be obtained through the selection of suitable prediction models for time series data as well as the adjustment of training algorithms.

Caregiver decision-making on young child schooling/care in the face of COVID-19: The influence of child, caregiver, and systemic factors.

In March 2020, U.S. schools and daycares largely shut down to manage the novel COVID-19 pandemic. As the country made efforts to reopen the economy, American parents faced difficult decisions regarding returning to work and securing schooling and care for their young children. During the summer and fall of 2020, caregivers (N = 1655) of children (N = 2408; ages 0 - 12 years) completed questionnaires assessing their decision-making process regarding their children's daycare or schooling situation. A mixed method approach (i.e., qualitative, quantitative assessments) was utilized. Outcomes indicated three main themes that impacted caregivers' choices: child factors, caregiver factors, and systemic factors. Caregivers experienced high levels of stress while worrying about their child's and family's health, job responsibilities, and risk of COVID-19 infection rates in their areas. Continued assessment of families and children during this time is warranted.

Pademics' Narratives: from skilled teacher to beginning daycare pedagogical coordinator

Based on narratives this article aims to analyze experiences of a competent teacher during the pandemic period took the job as a daycare Pedagogical Coordinator. First of all she words with young children in a public daycare facility center at west of Sao Paulo city. After that she also worked as a manager in another daycare facility center focused on babies in the same city. We have used the following theorical sources: Clandinin e Connely (2000);Cochran-Smith e Lytle (2015);Dalberg, Moss e Pence (2019) e Oliveira-Formosinho (2009). Through narratives we have figured out that the experiences of this teacher in early childhood education substantially influenced her actions as an entry level manager position. Despite conditions of the daycare building keeping doors closed due to COVID-19 pandemic, it was clear that the presence of a teacher in the classroom has never been more necessary.

Comparing susceptibility and contagiousness in concurrent outbreaks with a non-VOC and the VOC SARS-CoV-2 variant B.1.1.7 in daycare centers in Hamburg, Germany.

We describe two outbreaks of SARS-CoV-2 in daycare centers in the metropolitan area of Hamburg, Germany. The outbreaks occurred in rapid chronological succession, in neighborhoods with a very similar sociodemographic structure, thus allowing for cross-comparison of these events. We combined classical and molecular epidemiologic investigation methods to study infection entry, spread within the facilities, and subsequent transmission of infections to households. Epidemiologic and molecular evidence suggests a superspreading event with a non-variant of concern (non-VOC) SARS CoV-2 strain at the root of the first outbreak. The second outbreak involved two childcare facilities experiencing infection activity with the variant of concern (VOC) B.1.1.7 (Alpha). We show that the index cases in all outbreaks had been childcare workers, and that children contributed substantially to secondary transmission of SARS-CoV-2 infection from childcare facilities to households. The frequency of secondary transmissions in households originating from B.1.1.7-infected children was increased compared to children with non-VOC infections. Self-reported symptoms, particularly cough and rhinitis, occurred more frequently in B.1.1.7-infected children. Especially in light of the rapidly spreading VOC B.1.617.2 (Delta), our data underline the notion that rigorous SARS-CoV-2 testing in combination with screening of contacts regardless of symptoms is an important measure to prevent SARS-CoV-2 infection of unvaccinated individuals in daycare centers and associated households.

Unexpected Low Mortality on Covid-19 in Homeless During Spring Wave 2021

Introduction: COVID-19 virus disease specific mortality variant throughout all continents between 3 and 15 percent, depending on virus subtype and age, social and health status of the affected population. Groups at risk were seniors after 70, low socioeconomic groups, unvaccinated and groups with no access to health care, elderly and mental facilities residents, homeless and orphan facilities. Method and results: We have analyzed three cohorts of 702 homeless from clients from, Slovakia, Poland, Czech republic, Ukraine, Moldova, Serbia and found unexpectedly low specific mortality, probably due to isolation of those full-board centers from neighboring large towns in to life islands and few social contacts of this risk population during 2 wave because of church and social daycare centers closure. Conclusion: In conclusion, life island quarantine model powered by vaccination may decrease even more COVID-19 related mortality in expected winter or spring waves. © 2021. All Rights Reserved.

A Retrospective Outbreak Investigation of a COVID-19 Case Cluster in a Berlin Kindergarten, November 2020.

While SARS-CoV-2 infection activity in German kindergartens during the first year of the pandemic appeared to be overall low, outbreaks did occur. We retrospectively investigated an outbreak in November and December 2020 in a Berlin kindergarten participating in the Berlin Corona School and Kindergarten Study (BECOSS). Interviews were conducted with affected families regarding symptomatology, contact persons and possible sources of infection, as well as relevant information on the conditions on-site and infection prevention measures. A chronology of the outbreak was elaborated, and based on data on contacts and symptoms, we mapped the most likely chains of infection. Overall, 24 individuals, including ten educators, seven children, and seven household members, were infected with SARS-CoV-2 in a four-week time interval. Courses of infection ranged from asymptomatic to severe, with children less affected by symptoms. Viral spread within the facility seemed to occur mainly through kindergarten staff, while children primarily transmitted infections within their families. Interviewees reported that hygiene measures were not always adhered to inside the facility. To prevent outbreaks in kindergartens, especially in the light of current and newly emerging viral variants of concern, strict compliance to hygiene rules, staff vaccinations against SARS-CoV-2, and immediate reaction to suspected cases by quarantining and frequent testing seem reasonable measures.

[SARS-CoV-2 incidence, transmission, and containment measures in daycare centers during the COVID-19 pandemic-findings from the Corona Daycare Study]. / Infektionsgeschehen und Eindämmungsmaßnahmen in Kitas während der COVID-19-Pandemie ­ Erkenntnisse aus der Corona-KiTa-Studie.

BACKGROUND: Daycare centers are of substantial sociopolitical and pedagogical relevance; at the same time, the close contact of children in daycare groups among each other and with employees favors the transmission of infections. In the COVID-19 pandemic, questions arose about how infection events occur in daycare centers, what role daycare children play in the pandemic, and what protective and hygienic measures are implemented in daycare centers. From 06/2020 to 12/2021, we conducted the "Corona Day Care Study," in which we address pedagogical and infection epidemiological topics in a joint approach. METHODS: In the study, data are collected from different sources. Official reporting data as well as weekly data from daycare centers in the so-called KiTa Register are continuously evaluated. In addition, SARS-CoV­2 outbreaks in daycare centers are investigated on site by repeated sample collection and interviews. RESULTS: SARS-CoV­2 infection incidence in daycare centers or in daycare-aged children was very dynamic from 03/2020 to 05/2021. In the second and third pandemic waves, the number of SARS-CoV­2 outbreaks in daycare centers rose sharply, accompanied by a substantial increase in daycare and group closures. Most recently, the proportion of affected children in outbreaks increased steadily. However, preliminary examinations of SARS-CoV­2 outbreaks (n = 28) revealed that, on average, only a fraction of daycare contact persons (6.8%) were infected by child index cases. Transmission frequencies differed markedly between the individual daycare centers. DISCUSSION: The combination of regularly collected reporting and survey data as well as outbreak investigations allows a multilayered monitoring and understanding of infection events in daycare centers; its findings could be incorporated into recommendations for public health measures.

[Children in the COVID-19 pandemic and the public health service (ÖGD) : Data and reflections from Frankfurt am Main, Germany]. / Kinder in der COVID-19 Pandemie und der Öffentliche Gesundheitsdienst (ÖGD) : Daten und Überlegungen aus Frankfurt am Main.

BACKGROUND: The measures taken to combat the COVID-19 pandemic have severely restricted the opportunities for the development of children. This paper will discuss the reporting data of children and the public health department's activities against the background of the restrictions of school and leisure time offers as well as sports and club activities. MATERIALS AND METHODS: Reporting data from Frankfurt am Main, Hesse, were obtained using a SURVStat query for the calendar weeks 10/2020-28/2021 and from SURVNet (until 30 June 2021). Contact persons (CP) of SARS-CoV­2 positive persons from schools and daycare centers were screened for SARS-CoV­2 by PCR test. These results and those of rapid antigen testing, which has been mandatory for schoolchildren since April 2021, are presented. RESULTS: Until Easter break, the age-related seven-day incidence values per 100,000 for children 14 years of age and younger were lower than the overall incidence; it was only higher after rapid antigen-testing was mandatory for schoolchildren. Most children with SARS-CoV­2 had no or mild symptoms; hospitalization was rarely required and no deaths occurred. Contact tracing in schools and daycare centers found no positive contacts in most cases and rarely more than two. Larger outbreaks did not occur. CONCLUSION: SARS-CoV­2 infections in children appear to be less frequent and much less severe than in adults. Hygiene rules and contact management have proven themselves effective during times with high incidences in the local population without mandatory rapid antigen testing - and even with a high proportion of variants of concern (alpha and delta variants) in Germany. Against this background, further restriction of school and daycare operations appears neither necessary nor appropriate.

Surveillance of SARS-CoV-2 transmission in educational institutions, August to December 2020, Germany.

This study aims at providing estimates on the transmission risk of SARS-CoV-2 in schools and day-care centres. We calculated secondary attack rates (SARs) using individual-level data from state-wide mandatory notification of index cases in educational institutions, followed by contact tracing and PCR-testing of high-risk contacts. From August to December 2020, every sixth of overall 784 independent index cases was associated with secondary cases in educational institutions. Monitoring of 14 594 institutional high-risk contacts (89% PCR-tested) of 441 index cases during quarantine revealed 196 secondary cases (SAR 1.34%, 0.99-1.78). SARS-CoV-2 infection among high-risk contacts was more likely around teacher-indexes compared to student-/child-indexes (incidence rate ratio (IRR) 3.17, 1.79-5.59), and in day-care centres compared to secondary schools (IRR 3.23, 1.76-5.91), mainly due to clusters around teacher-indexes in day-care containing a higher mean number of secondary cases per index case (142/113 = 1.26) than clusters around student-indexes in schools (82/474 = 0.17). In 2020, SARS-CoV-2 transmission risk in educational settings was low overall, but varied strongly between setting and role of the index case, indicating the chance for targeted intervention. Surveillance of SARS-CoV-2 transmission in educational institutions can powerfully inform public health policy and improve educational justice during the pandemic.

Factors Related to Breastfeeding Support in Lebanese Daycare Centers: A Qualitative Study among Daycare Directors and Employees.

Breastfeeding has an important impact on maternal and child health, and is affected by several factors influencing its initiation and continuation. This qualitative study aimed to assess the main promoting and hindering factors for breastfeeding support in Lebanese daycare centers (DCCs), through the perspective of their directors and employees. The study was based on semi-structured interviews with 13 directors and 9 employees. It explored the influence of various cognitive factors as well as different environment types (physical, economic, political, and sociocultural) on their breastfeeding support. Findings suggested the directors and employees valued improving breastfeeding support in DCCs and the physical set-up of the DCCs allowed for this. However, various other factors restricted their abilities to support breastfeeding in the DCC, including limited knowledge and training on the topic, absence of written internal policies on breastfeeding, lack of enforcement in the application of national policies, and the current mothers' work policies that negatively influenced the decision to breastfeed. Improvements could be achieved through integrated interventions, targeting the interaction of internal DCCs factors and national and DCCs breastfeeding policies, as well as several social factors, to create a multilevel approach targeting breastfeeding continuation support in breastfeeding-friendly DCCs in Lebanon and the region.

Outbreak investigation of SARS-CoV-2 transmission in an emergency childcare centre.

OBJECTIVE: To characterize SARS-CoV-2 transmission following a COVID-19 outbreak in an emergency childcare centre (ECCC) in April 2020 in Quebec, Canada. METHODS: The study population consisted of all the children and employees who attended the ECCC as well as household contacts of the confirmed COVID-19 cases. Of the 120 individuals in the study, five cases were confirmed by epidemiological link and 25 were identified as COVID-19 by RT-PCR among which 19 were analyzed by viral whole genome sequencing. Descriptive epidemiology, social network visualization, and phylogenetic analysis were used to characterize viral transmission. RESULTS: Phylogenetic analysis identified two separate introductions of distinct lineages of SARS-CoV-2 and estimated an average effective reproductive number of Re = 1.9 (range 0.9-4.9) with a mean doubling time of 3.2 days (range 2.1-5.2). The first and most prevalent lineage was introduced by two asymptomatic children who were likely infected by their parent, a confirmed COVID-19 case working in a long-term care centre. Among infected household adults, attack rates were significantly higher in mothers than in fathers (risk ratio = 4.5; 95% CI 1.1-18.7). The extent of transmission makes it one of the largest documented outbreaks in a daycare in Canada. CONCLUSION: The analyses carried out showed the probable origin and direction of the transmission of the infection (adult-child, child-adult, and child-child), thus highlighting how asymptomatic children can efficiently transmit SARS-CoV-2.

RéSUMé: OBJECTIF: Caractériser la transmission du SRAS-CoV-2 à la suite d'une éclosion de COVID-19 dans un service de garde d'urgence en milieu scolaire (SGUMS) en avril 2020 au Québec, Canada. MéTHODES: La population à l'étude était composée de tous les enfants et employés ayant fréquenté le SGUMS ainsi que les contacts familiaux des cas confirmés de COVID-19. Sur les 120 personnes à l'étude, cinq cas ont été confirmés par lien épidémiologique et 25 par RT-PCR. Parmi ces derniers, 19 ont été analysés par séquençage viral du génome entier. La caractérisation de la transmission a été réalisée à l'aide d'analyses descriptives et phylogénétiques ainsi que de la visualisation de réseaux sociaux. RéSULTATS: L'analyse phylogénétique a identifié deux introductions de lignées distinctes du SRAS-CoV-2 et un taux de reproduction net Re = 1,9 (étendue 0,9­4,9) avec un temps moyen de doublement de 3,2 jours (étendue 2,1­5,2). La première lignée, et la plus répandue, a été introduite par deux enfants asymptomatiques qui ont probablement été infectés par leur parent, un travailleur de la santé atteint de COVID-19. Dans les noyaux familiaux, les taux d'attaque étaient significativement plus élevés chez les mères que chez les pères (rapport de risque = 4,5 ; IC à 95 % 1,1­18,7). L'ampleur de la transmission en fait de celle-ci la plus importante éclosion documentée dans un service de garde au Canada. CONCLUSION: Cette étude a permis de déterminer l'origine et la direction probables de la transmission de l'infection (adulte-enfant, enfant-adulte et enfant-enfant) et démontrer que les enfants asymptomatiques peuvent transmettre le SRAS-CoV-2.