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As countries in Europe implement strategies to control the COVID-19 pandemic, different options are chosen regarding schools. Through a stochastic age-structured transmission model calibrated to the observed epidemic in Île-de-France in the first wave, we explored scenarios of partial, progressive, or full school reopening. Given the uncertainty on children’s role, we found that reopening schools after lockdown may increase COVID-19 cases, yet protocols exist to keep the epidemic controlled. Under a scenario with stable epidemic activity if schools were closed, reopening pre-schools and primary schools would lead to up to 76% [67, 84]% occupation of ICU beds if no other school level reopened, or if middle and high schools reopened later. Immediately reopening all school levels may overwhelm the ICU system. Priority should be given to pre- and primary schools allowing younger children to resume learning and development, whereas full attendance in middle and high schools is not recommended for stable or increasing epidemic activity. Large-scale test and trace is required to keep the epidemic under control. Ex-post assessment shows that progressive reopening of schools, limited attendance, and strong adoption of preventive measures contributed to a decreasing epidemic after lifting the first lockdown. The role of children in the spread of COVID-19 is not fully understood, and the circumstances under which schools should be opened are therefore debated. Here, the authors demonstrate protocols by which schools in France can be safely opened without overwhelming the healthcare system.

ABSTRACTThe novel coronavirus (SARS-CoV-2) causes pandemic of viral pneumonia. The evolution and mutational events of the SARS-CoV-2 genomes are critical for controlling virulence, transmissibility, infectivity, severity of symptoms and mortality associated to this infectious disease. We collected and investigated 309 SARS-CoV-2 genomes from patients infected in France. Detailed genome cartography of all mutational events (SNPs, indels) was reported and correlated to clinical features of patients. A comparative analysis between our 309 SARS-CoV-2 genomes from French patients and the reference Wuhan coronavirus genome revealed 315 substitution mutations and six deletion events: ten were in 5’/3’ UTR, 178 were nonsynonymous, 126 were synonymous and one generated a stop codon. Six different deleted areas were also identified in nine viral variants. In particular, 30 substitution mutations (18 nonsynonymous) and one deletion (Δ21765-21770) concerned the spike S glycoprotein. An average of 7.8 mutational events (+/- 1.7 SD) and a median of 8 (range, 7-9) were reported per viral isolate. Comparative analyses and clustering of specific mutational signatures in 309 genomes disclose several divisions in groups and subgroups combining their geographical and phylogenetic origin. Clinical outcomes of the 309 COVID-19-infected patients were investigated according to the mutational signatures of viral variants. These findings highlight the genome dynamics of the coronavirus 2019-20 and shed light on the mutational landscape and evolution of this virus. Inclusion of the French cohort enabled us to identify 161 novel mutations never reported in SARS-CoV-2 genomes collected worldwide. These results support a global and continuing surveillance of the emerging variants of the coronavirus SARS-CoV-2.

Dès les premières semaines de l’épidémie de la Covid-19, en France, plusieurs voix se sont levées pour dire que l’heure n’était pas à la réflexion éthique, mais à l’action, en soulignant néanmoins l’importance d’un retour d’expérience à l’issue de l’urgence. Dans cette visée, le Centre d’éthique clinique de l’AP-HP a proposé, dès la fin du 1er confinement national, à des soignants, comme à des patients ou à des proches, de revenir, s’ils le souhaitaient, sur les questionnements ou les difficultés éthiques rencontrées pendant cette période (ce qu’il a appelé des « relectures éthiques »). Entre mai et septembre 2020, 31 professionnels y ont participé, 1 seul patient (médecin à la retraite) a été rencontré et aucun proche. Cet article souhaite partager la façon dont ces professionnels sont revenus, dans l’après-coup, sur les premiers mois de la crise. Plus d’une année plus tard, à l’heure où ce qui était « inhabituel » commence par devenir « ordinaire », et le « retour à la vie normale » semble à l’horizon, il n’est pas inutile de rappeler leurs réactions, leurs interrogations et leurs malaises. Au croisement des entretiens, c’est un questionnement quant à ce que soigner veut dire aujourd’hui et au rôle de la médecine en contexte de crise que l’on voit émerger. From the beginning of the Covid-19 pandemic in France, many argued that now was the time for action, not ethics, while acknowledging the need for feedback once the crisis had passed. To this end, the Parisian clinical ethics’ center suggested that health professionals, patients, and families come back on difficulties or questions they might have had during the first national lockdown once it was over. We called it ethical debriefs. Between May and September 2021, 31 professionals agreed to participate, but only 1 patient (a retired physician) and no proxy was met. The aim of this article is to share how these health professionals revisited the first months of the crisis. Indeed today, more than one year since Covid started and as what was once unusual is becoming common practice, it is useful not to forget how they reacted, what their questions were and where did their ethical difficulties lie at that time. Now that coming back to normal might be conceivable, all these interviews highlight the importance of a questioning on what caring for patients means nowadays, as well as on the definition of role of medicine in a context of crisis.

In addition to providing life-giving nutrients and other substances to the breastfed infant, human milk can also represent a vehicle of pathogen transfer. As such, when an infectious disease outbreak, epidemic, or pandemic occurs—particularly when it is associated with a novel pathogen—the question will naturally arise as to whether the pathogen can be transmitted through breastfeeding. Until high-quality data are generated to answer this question, abandonment of breastfeeding due to uncertainty can result. The COVID-19 pandemic, which was in full swing at the time this document was written, is an excellent example of this scenario. During these times of uncertainty, it is critical for investigators conducting research to assess the possible transmission of pathogens through milk, whether by transfer through the mammary gland or contamination from respiratory droplets, skin, breast pumps, and milk containers, and/or close contact between mother and infant. To promote the most rigorous science, it is critical to outline optimal methods for milk collection, handling, storage, and analysis in these situations, and investigators should openly share their methods in published materials. Otherwise, the risks of inconsistent test results from preanalytical and analytical variation, false positives, and false negatives are unacceptably high and the ability to provide public health guidance poor. In this study, we provide ‘‘best practices’’ for collecting human milk samples for COVID-19 research with the intention that this will also be a useful guide for future pandemics. Peer reviewed

ABSTRACT The COVID-19, caused by the novel coronavirus SARS-CoV-2, has broken out of control all over the globe and put the majority of the world under lockdown. There have been no specific antiviral medications for SARS-CoV-2 while vaccines are still under development. Thus, rapid diagnosis and necessary public health measures are currently key parts to contain the pandemic. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) is the gold standard method for SARS-CoV-2 detection. However, this method is not suitable for point-of-care (POC) diagnosis because of the timeconsuming procedure, the requirements of biosafety conditions and expensive equipment. In this study, the colorimetric isothermal nucleic acid amplification tests (iNAATs) for SARS-CoV-2 based on loop-mediated isothermal amplification (LAMP), cross-priming amplification (CPA), and polymerase spiral reaction (PSR) were developed and compared. The three methods exhibited similar performance with the limit of detection (LOD) as low as just 1 copy per reaction when evaluated on the synthetic DNA fragments. The results can be read with naked eyes within 30 minutes without crossreactivity to closely related coronaviruses. When tested with SARS-CoV-2 extracted genomic-RNA, LAMP outperformed both CPA and PSR assays. Moreover, the direct detection of SARS-CoV-2 in simulated patient samples (oropharyngeal and nasopharyngeal swabs) by colorimetric iNAATs was also successful. Further preparation of the lyophilized reagents for LAMP reactions revealed that the freeze-dried, ready-to-use kit maintained the sensitivity and LOD value of the liquid assays. These results strongly indicate that the colorimetric lyophilized LAMP test kit developed herein is highly suitable for detecting SARS-CoV-2 at POC.

AbstractBluetongue virus (BTV) is an arbovirus transmitted by blood-feeding midges to a wide range of wild and domestic ruminants. In this report, we showed that BTV, through its virulence non-structural protein NS3 (BTV-NS3), is able to activate the MAPK/ERK pathway. In response to growth factors, the MAPK/ERK pathway activates cell survival, differentiation, proliferation and protein translation but can also lead to the production of several inflammatory cytokines. By combining immunoprecipitation of BTV-NS3 and mass spectrometry analysis from both BTV-infected and NS3-transfected cells, we identified the serine/threonine-protein kinase B-Raf (BRAF), a crucial player of the MAPK/ERK pathway, as a new cellular interactor of BTV-NS3. BRAF silencing led to a significant decrease of the MAPK/ERK activation by BTV supporting a model where BTV-NS3 interacts with BRAF to activate this signaling cascade. Furthermore, the intrinsic ability of BTV-NS3 to bind BRAF and activate the MAPK/ERK pathway is conserved throughout multiple serotypes/strains but appears to be specific to BTV compared to other members ofOrbivirusgenus. Inhibition of MAPK/ERK pathway with U0126 reduced viral titers, suggesting that BTV manipulates this pathway for its own replication. Therefore, the activation of the MAPK/ERK pathway by BTV-NS3 could benefit to BTV replication by promoting its own viral protein synthesis but could also explain the deleterious inflammation associated with tissue damages as already observed in severe cases of BT disease. Altogether, our data provide molecular mechanisms to explain the role of BTV-NS3 as a virulence factor and determinant of pathogenesis.ImportanceBluetongue Virus (BTV) is responsible of the non-contagious arthropod-borne disease Bluetongue (BT) transmitted to ruminants by blood-feeding midges. Despite the fact that BTV has been extensively studied, we still have little understanding of the molecular determinants of BTV virulence. In this report, we found that the virulence protein NS3 interacts with BRAF, a key component of the MAPK/ERK pathway. In response to growth factors, this pathway promotes cell survival, increases protein translation but also contributes to the production of inflammatory cytokines. We showed that BTV-NS3 enhances the MAPK/ERK pathway and this activation is BRAF-dependent. Our results demonstrate, at the molecular level, how a single virulence factor has evolved to target a cellular function to ensure its viral replication. On the other hand, our findings could also explain the deleterious inflammation associated with tissue damages as already observed in severe cases of BT disease.

Background: As novel coronavirus disease (COVID-19) cases continue to steeply rise globally within an unprecedented short period of time, solid evidence from large randomised controlled trials is still lacking. Currently, numerous trials testing potential treatment and preventative options are undertaken globally. Objectives: We summarised all currently registered clinical trials examining treatment and prevention options for COVID-19 pneumonia. Additionally, we evaluated the quality of the retrieved interventional studies. Data sources: The ClinicalTrials.gov, the Chinese Clinical Trial Registry and the European Union Clinical Trials Register were systematically searched. Study eligibility criteria: Registered clinical trials examining treatment and/or prevention options for COVID-19 were included. No language, country or study design restrictions were applied. Withdrawn, cancelled studies and trials not reporting therapeutic or preventative strategies for COVID-19 were excluded. Participants and interventions: No restrictions in terms of participants age and medical background or type of intervention were enforced. Methods: The registries were searched using the term "coronavirus" or "COVID-19" from their inception until 26th March 2020. Additional manual search of the registries was also performed. Eligible studies were summarised and tabulated. Interventional trials were methodologically analysed, excluding expanded access studies and trials testing Traditional Chinese Medicine. Results: In total, 309 trials evaluating therapeutic management options, 23 studies assessing preventive strategies and 3 studies examining both were retrieved. Interventional treatment studies were mostly randomised (n=150, 76%) and open-label (n=73, 37%) with a median number of planned inclusions of 90 (IQR 40-200). Major categories of interventions that are currently being investigated are discussed. Conclusion: Numerous clinical trials have been registered since the onset of the COVID-19 pandemic. Summarised data on these trials will assist physicians and researchers to promote patient care and guide future research efforts for COVID-19 pandemic containment. However, up to the end of March, 2020, significant information concerning reported trials was lacking.

ABSTRACTClinical manifestations of COVID-19 caused by the novel coronavirus SARS-CoV-2 are associated with age. While children are largely spared from severe respiratory disease, they can present with a SARS-CoV-2-associated multisystem inflammatory syndrome (MIS-C) similar to Kawasaki’s disease. Here, we show distinct antibody (Ab) responses in children with MIS-C compared to adults with severe COVID-19 causing acute respiratory distress syndrome (ARDS), and those who recovered from mild disease. There was a reduced breadth and specificity of anti-SARS-CoV-2-specific antibodies in MIS-C patients compared to the COVID patient groups; MIS-C predominantly generated IgG Abs specific for the Spike (S) protein but not for the nucleocapsid (N) protein, while the COVID-19 cohorts had anti-S IgG, IgM and IgA Abs, as well as anti-N IgG Abs. Moreover, MIS-C patients had reduced neutralizing activity compared to both COVID-19 cohorts, indicating a reduced protective serological response. These results suggest a distinct infection course and immune response in children and adults who develop severe disease, with implications for optimizing treatments based on symptom and age.