Tixagevimab-cilgavimab (AZD7442) for the treatment of patients hospitalized with COVID-19 (DisCoVeRy): A phase 3, randomized, double-blind, placebo-controlled trial (preprint)

Background Tixagevimab and cilgavimab (AZD7442) are two monoclonal antibodies developed by AstraZeneca for the pre-exposure prophylaxis and treatment of patients infected by SARS-CoV-2. Its effectiveness and safety in patients hospitalized with COVID-19 was not known at the outset of this trial. Methods DisCoVeRy is a phase 3, adaptive, multicentre, randomized, controlled trial conducted in 63 sites in Europe. Participants were randomly assigned (1:1) to receive placebo or tixagevimab-cilgavimab in addition to standard of care. The primary outcome was the clinical status at day 15 measured by the WHO seven-point ordinal scale. Several clinical, virological, immunological and safety endpoints were also assessed. Findings Due to slow enrolment, recruitment was stopped on July 1st, 2022. The antigen positive modified intention-to-treat population (mITT) was composed of 173 participants randomized to tixagevimab-cilgavimab (n=91) or placebo (n=82), 91.9% (159/173) with supplementary oxygen, and 47.4% (82/173) previously vaccinated at inclusion. There was no significant difference in the distribution of the WHO ordinal scale at day 15 between the two groups (odds ratio (OR) 0.93, 95%CI [0.54-1.61]; p=0.81) nor in any clinical, virological or safety secondary endpoints. In the global mITT (n=226), neutralization antibody titers were significantly higher in the tixagevimab-cilgavimab group/patients compared to placebo at day 3 (Least-square mean differences (LSMD) 1.44, 95% Confidence interval (CI) [1.20-1.68]; p < 10-23) and day 8 (LSMD 0.91, 95%CI [0.64-1.18]; p < 10-8) and it was most important for patients infected with a pre-omicron variant, both at day 3 (LSMD 1.94, 95% CI [1.67-2.20], p < 10-25) and day 8 (LSMD 1.17, 95% CI [0.87-1.47], p < 10-9), with a significant interaction (p < 10-7 and p=0.01 at days 3 and 8, respectively). Interpretation There were no significant differences between tixagevimab-cilgavimab and placebo in clinical endpoints, however the trial lacked power compared to prespecified calculations. Tixagevimab-cilgavimab was well tolerated, with low rates of treatment related events.

Could faecal viral excretion explain gastrointestinal symptoms in COVID-19 patients: co- infection involvement? (preprint)

Objectives: Physiopathological mechanisms responsible for digestive symptoms during COVID-19 are still unclear. The aim of this study was to determine the influence of faecal viral shedding on digestive symptoms and propose differential diagnoses to better understand the gastrointestinal clinical spectrum during acute COVID-19.Methods: Patients were included if one stool sample was available for microbiological investigation. Microbiological analysis consisted of syndromic PCR screening, and parasitological investigation included microsporidia and multiplex protozoa PCR. SARS-CoV-2 infection was diagnosed by viral detection (on respiratory samples and frozen stool samples) and by serology when necessary. Collected epidemiological, clinical, radiological, biological data and clinical course were compared according to COVID-19 status, faecal SARS-CoV-2 shedding and co-infection status.Results: 50 COVID+ and 67 COVID- patients were included. Faecal viral shedding was detected in 50% of stool samples and was associated with higher viral load in the upper respiratory tract. There was no difference in the proportion of detected enteric pathogens between COVID-19 status. No impact was observed on clinical course regardless of COVID-19 status, faecal SARS-CoV-2 shedding and coinfection status.Conclusions: SARS-CoV-2 shedding and enteric pathogen involvement in gastrointestinal presentation is still unclear. However, differential diagnostic investigation revealed frequently occurring common enteric pathogens in COVID-19 patients.

Remdesivir for the treatment of hospitalised patients with COVID-19: final results from the DisCoVeRy randomised, controlled, open-label trial (preprint)

Background: The antiviral efficacy of remdesivir is still controversial. We aimed at evaluating its clinical effectiveness in hospitalised patients with COVID-19, with indication of oxygen and/or ventilator support. Following prior publication of preliminary results, here we present the final results after completion of data monitoring. Methods: In this European multicentre, open-label, parallel-group, randomised, controlled trial (DisCoVeRy, NCT04315948, EudraCT2020-000936-23), participants were randomly allocated to receive usual standard of care (SoC) alone or in combination with remdesivir, lopinavir/ritonavir, lopinavir/ritonavir and IFN-beta-1a, or hydroxychloroquine. Adult patients hospitalised with COVID-19 were eligible if they had clinical evidence of hypoxemic pneumonia, or required oxygen supplementation. Exclusion criteria included elevated liver enzyme, severe chronic kidney disease, any contra-indication to one of the studied treatments or their use in the 29 days before randomization, or use of ribavirin, as well as pregnancy or breast-feeding. Here, we report results for remdesivir + SoC versus SoC alone. Remdesivir was administered as 200 mg infusion on day 1, followed by once daily infusions of 100 mg up to 9 days, for a total duration of 10 days. It could be stopped after 5 days if the participant was discharged. Treatment assignation was performed via web-based block randomisation stratified on illness severity and administrative European region. The primary outcome was the clinical status at day 15 measured by the WHO 7-point ordinal scale, assessed in the intention-to-treat population. Findings: Between March 22nd, 2020 and January 21st, 2021, 857 participants were randomised to one of the two arms in 5 European countries and 843 participants were included for the evaluation of remdesivir (control, n=423; remdesivir, n=420). At day 15, the distribution of the WHO ordinal scale was as follow in the remdesivir and control groups, respectively: Not hospitalized, no limitations on activities: 62/420 (14.8%) and 72/423 (17.0%); Not hospitalized, limitation on activities: 126/420 (30%) and 135/423 (31.9%); Hospitalized, not requiring supplemental oxygen: 56/420 (13.3%) and 31/423 (7.3%); Hospitalized, requiring supplemental oxygen: 75/420 (17.9%) and 65/423 (15.4%); Hospitalized, on non-invasive ventilation or high flow oxygen devices: 16/420 (3.8%) and 16/423 (3.8%); Hospitalized, on invasive mechanical ventilation or ECMO: 64/420 (15.2%) and 80/423 (18.9%); Death: 21/420 (5%) and 24/423 (5.7%). The difference between treatment groups was not statistically significant (OR for remdesivir, 1.02, 95% CI, 0.62 to 1.70, P=0.93). There was no significant difference in the occurrence of Serious Adverse Events between treatment groups (remdesivir, n=147/410, 35.9%, versus control, n=138/423, 32.6%, p=0.29). Interpretation: Remdesivir use for the treatment of hospitalised patients with COVID-19 was not associated with clinical improvement at day 15. Funding: European Union Commission, French Ministry of Health, DIM One Health Ile-de-France, REACTing, Fonds Erasme-COVID-ULB; Belgian Health Care Knowledge Centre (KCE), AGMT gGmbH, FEDER "European Regional Development Fund", Portugal Ministry of Health, Portugal Agency for Clinical Research and Biomedical Innovation. Remdesivir was provided free of charge by Gilead.

Rapid characterization of a Delta-Omicron SARS-CoV-2 recombinant detected in Europe (preprint)

Recombination is a crucial process in the evolution of many organisms. Although the evolutionary reasons behind its occurrence in RNA viruses are debated, this phenomenon has been associated with major epidemiological events such as virus host range expansion, antigenic shift or variation in virulence 1,2, and this process occurs frequently in positive strand RNA viruses such as coronaviruses. The SARS-CoV-2 pandemic has been associated with the repeated emergence of variants of concern presenting increased transmissibility, severity or immune escape 3. The recent extensive circulation of Delta worldwide and its subsequent replacement by viruses of the Omicron lineage 4 (BA.1 then BA.2), have created conditions for genetic exchanges between viruses with both genetic diversity and phenotypic specificities 5-7. Here we report the identification and in vitro and in vivo characterization of a Delta-Omicron recombinant in Europe. This recombinant exhibits immune escape properties similar to Omicron, while its behavior in mice expressing the human ACE2 receptor is more similar to Delta. This recombinant provides a unique and natural opportunity to better understand the genotype to phenotype links in SARS-CoV-2.

An open-label randomized, controlled trial of the effect of lopinavir/ritonavir, lopinavir/ritonavir plus IFN-β-1a and hydroxychloroquine in hospitalized patients with COVID-19 – Final results from the DisCoVeRy trial (preprint)

Objectives We evaluated the clinical, virological and safety outcomes of lopinavir/ritonavir, lopinavir/ritonavir-interferon (IFN)-β-1a, hydroxychloroquine or remdesivir in comparison to standard of care (control) in COVID-19 inpatients requiring oxygen and/or ventilatory support. While preliminary results were previously published, we present here the final results, following completion of the data monitoring. Methods We conducted a phase 3 multi-centre open-label, randomized 1:1:1:1:1, adaptive, controlled trial (DisCoVeRy), add-on trial to Solidarity ( NCT04315948 , EudraCT2020-000936-23). The primary outcome was the clinical status at day 15, measured by the WHO 7-point ordinal scale. Secondary outcomes included SARS-CoV-2 quantification in respiratory specimens, pharmacokinetic and safety analyses. We report the results for the lopinavir/ritonavir-containing arms and for the hydroxychloroquine arm, which were stopped prematurely. Results The intention-to-treat population included 593 participants (lopinavir/ritonavir, n=147; lopinavir/ritonavir-IFN-β-1a, n=147; hydroxychloroquine, n=150; control, n=149), among whom 421 (71.0%) were male, the median age was 64 years (IQR, 54-71) and 214 (36.1%) had a severe disease. The day 15 clinical status was not improved with investigational treatments: lopinavir/ritonavir versus control, adjusted odds ratio (aOR) 0.82, (95% confidence interval [CI] 0.54-1.25, P=0.36); lopinavir/ritonavir-IFN-β-1a versus control, aOR 0.69 (95%CI 0.45-1.05, P=0.08); hydroxychloroquine versus control, aOR 0.94 (95%CI 0.62-1.41, P=0.76). No significant effect of investigational treatment was observed on SARS-CoV-2 clearance. Trough plasma concentrations of lopinavir and ritonavir were higher than those expected, while those of hydroxychloroquine were those expected with the dosing regimen. The occurrence of Serious Adverse Events was significantly higher in participants allocated to the lopinavir/ritonavir-containing arms. Conclusion In adults hospitalized for COVID-19, lopinavir/ritonavir, lopinavir/ritonavir-IFN-ß-1a and hydroxychloroquine did not improve the clinical status at day 15, nor SARS-CoV-2 clearance in respiratory tract specimens.

Modeling remdesivir antiviral efficacy in COVID-19 hospitalized patients of the randomized, controlled, open-label DisCoVeRy trial (preprint)

Despite several clinical studies, the antiviral efficacy of remdesivir in COVID-19 hospitalized patients remains controversial. We analyzed nasopharyngeal normalized viral loads collected in the 29 days following randomization from 665 hospitalized patients included in the DisCoVeRy trial, allocated to either standard of care (SoC, N=329) or SoC + remdesivir for 10 days (N=336). We used a mathematical model to reconstruct viral kinetic profiles and estimate the antiviral efficacy of remdesivir in reducing viral production. To identify factors associated with viral kinetics, additional analyses were conducted stratified either on time of treatment initiation ([≤] or > 7 days since symptom onset) or viral load at randomization (< or [≥] 3.5 log10 copies/104 cells). In our model, remdesivir reduced viral production by 2-fold on average (95%CI: 1.5-3.2). Using the estimated parameter of the model, simulations predict that remdesivir reduces time to viral clearance by 0.7 day compared to SoC, with large inter-individual variabilities (Inter-Quartile Range, IQR: 0.0-1.3 days). Exploratory analyses suggest that remdesivir had a larger impact in patients with a high viral load at randomization, reducing viral production by 5-fold on average (95%CI: 2.8-25), leading to a predicted median reduction in the time to viral clearance of 2.4 days (IQR: 0.9-4.5 days). In summary, our model shows that remdesivir reduces viral production from infected cells by a factor 2, leading to a median reduction of 0.7 days in the time to viral clearance compared to SoC. The efficacy was larger in patients with high level of viral load at treatment initiation. One sentence summaryRemdesivir reduces the time to SARS-CoV-2 clearance by 1 day in hospitalized patients, and up to 3 days in those with high viral load at admission.

Self-testing and vaccination against COVID-19 to minimize school closure (preprint)

Schools were largely closed in 2020-2021 to counter COVID-19 spread, impacting students education and well-being. With highly contagious variants expanding in Europe while vaccine hesitancy persists, safe options to maintain schools open are urgently needed. We developed an agent-based model of SARS-CoV-2 transmission in school. We used empirical contact data measured in a primary and a secondary school in France, and field estimates for adherence to screening from 683 schools during the spring 2021 wave. Examining different screening protocols, we performed a cost-benefit analysis for varying epidemic conditions and vaccination scenarios. In a partially immunized school population, weekly screening would reduce the number of cases on average by 24% in the primary and 53% in the secondary school compared to symptom-based testing alone, if R=1.3 and 50% adhered to screening. This adherence was met in primary schools (53% (95% confidence interval 21-85%)), but insufficient participation was recorded in secondary schools (10% (1-38%) in middle schools, 6% (2-12%) in high schools). Regular screening would also reduce by 90% the number of student-days lost compared to reactive class closure. No difference was predicted when fully vaccinating teachers, due to their limited number and mixing. Partially vaccinating adolescents would still require regular screening for additional control (20% case reduction with 50% vaccinated students). In the upcoming fall, COVID-19 epidemic will likely continue to pose a risk to the safe opening of schools. Increasing vaccination coverage in adolescents and implementing regular testing while largely incentivizing adherence are essential steps to keep schools open.

Remdesivir for the Treatment of Hospitalised Patients with COVID-19 (DisCoVeRy): A Randomised, Controlled, Open-Label Trial (preprint)

Background: The antiviral efficacy of remdesivir is still controversial. We aimed at evaluating its clinical effectiveness in patients with COVID-19 requiring oxygen and/or ventilator support.Methods: In this European multicentre, open-label, parallel-group, randomised, controlled trial in adults hospitalised with COVID-19 (DisCoVeRy, NCT04315948; EudraCT2020-000936-23), participants were randomly allocated to receive usual standard of care alone or in combination with intravenous remdesivir (200 mg on day 1, then 100 mg once-daily for 9 days or until discharge). Treatment assignation was performed via web-based randomisation stratified on illness severity and administrative European region. The primary outcome was the clinical status at day 15 measured by the WHO 7-point ordinal scale, assessed in the intention-to-treat population.Findings: Between March 22nd, 2020 and January 21st, 2021, 857 participants were randomised to one of the two arms in 5 European countries and 832 participants were included for the evaluation of remdesivir (control, n=418; remdesivir, n=414). There was no difference in the clinical status neither at day 15 between treatment groups (OR for remdesivir, 0.98, 95% CI, 0.77 to 1.25, P=0.85) nor at day 29. The proportion of deaths at day 28 was not significantly different between control (8.9%) and remdesivir (8.2%) treatment groups (OR for remdesivir, 0.93 95%CI 0.57 to 1.52, P=0.77). There was also no difference on SARS-CoV-2 viral kinetics (effect of remdesivir on viral load slope, -0.004 log10 cp/10,000 cells/day, 95% CI, -0.03 to 0.02, P=0.75). There was no significant difference in the occurrence of Serious Adverse Events between treatment groups.Interpretation: The use of remdesivir for the treatment of hospitalised patients with COVID-19 was not associated with clinical improvement at day 15 or day 29, nor with a reduction in mortality, nor with a reduction in SARS-CoV-2 RNA.Trial Registration: DisCoVeRy, NCT04315948; EudraCT2020-000936-23Funding: European Union Commission, French Ministry of Health, DIM One Health Île-de-France, REACTing, Fonds Erasme-COVID-ULB; Belgian Health Care Knowledge Centre (KCE)Declaration of Interests: Dr. Costagliola reports grants and personal fees from Janssen, personal fees from Gilead, outside the submitted work. Dr. Mentré reports grants from INSERM Reacting (French Government), grants from Ministry of Health (French Government), grants from European Commission, during the conduct of the study; grants from Sanofi, grants from Roche, outside the submitted work. Dr. Hites reports grants from The Belgian Center for Knowledge (KCE), grants from Fonds Erasme-COVID-ULB, during the conduct of the study; personal fees from Gilead, outside the submitted work. Dr. Mootien reports non-financial support from GILEAD, outside the submitted work. Dr. Gaborit reports non-financial support from Gilead, non- financial support from MSD, outside the submitted work. Dr. Botelho-Nevers reports other from Pfizer, other from Janssen, outside the submitted work. Dr. Lacombe reports personal fees and non-financial support from Gilead, personal fees and non-financial support from Janssen, personal fees and non-financial support from MSD, personal fees and non-financial support from ViiV Healthcare, personal fees and non-financial support from Abbvie, during the conduct of the study. Dr. Wallet reports personal fees and non-financial support from Jazz pharmaceuticals, personal fees and non-financial support from Novartis, personal fees and nonPage financial support from Kite-Gilead, outside the submitted work. Dr. Kimmoun reports personal fees from Aguettan, personal fees from Aspen, outside the submitted work. Dr. Thiery reports personal fees from AMGEN, outside the submitted work. Dr. Burdet reports personal fees from Da Volterra, personal fees from Mylan Pharmaceuticals, outside the submitted work. Dr. Poissy reports personal fees from Gilead for lectures, outside the submitted work. Dr. Goehringer reports personal fees from Gilead Sciences, non-financial support from Gilead Sciences, grants from Biomerieux, non-financial support from Pfizer, outside the submitted work. Dr. Peytavin reports personal fees from Gilead Sciences, personal fees from Merck France, personal fees from ViiV Healthcare, personal fees from TheraTechnologies, outside the submitted work. Dr. Danion reports personal fees from Gilead, outside the submitted work. Dr. Raffi reports personal fees from Gilead, personal fees from Janssen, personal fees from MSD, personal fees from Abbvie, personal fees from ViiV Healthcare, personal fees from Theratechnologies, personal fees from Pfizer, outside the submitted work. Dr. Gallien reports personal fees from Gilead, personal fees from Pfizer, personal fees from ViiV, personal fees from MSD, outside the submitted work; and has received consulting fee from Gilead in August 2020 to check the registration file of remdesivir for the French administration. Dr. Nseir reports personal fees from MSD, personal fees from Pfizer, personal fees from Gilead, personal fees from Biomérieux, personal fees from BioRad, outside the submitted work. Dr. Lefèvre reports personal fees from Mylan, personal fees from Gilead, outside the submitted work. Dr. Guedj reports personal fees from Roche, outside the submitted work. Other authors have nothing to disclose.Ethics Approval Statement: The trial was approved by the Ethics Committee (CPP Ile-de-France-III, approval #20.03.06.51744), and is sponsored by the Institut national de la santé et de la recherche médicale (Inserm, France); it was conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all included participants (or their legal representatives if unable to consent). The present analysis is based on the protocol v11.0 of December 12th, 2020.

Innate immune deficiencies in patients with COVID-19 (preprint)

COVID-19 can cause acute respiratory distress syndrome (ARDS), leading to death in a significant number of individuals. Evidence of a strong role of the innate immune system is accumulating, but the precise cells and mechanism involved remain unclear. In this study, we investigated the links between circulating innate phagocyte phenotype and functions and severity in COVID-19 patients. Eighty-four consecutive patients were included, 44 of which were in intensive care units (ICU). We performed an in-depth phenotyping of neutrophil and monocyte subpopulations and measured soluble activation markers in plasma. Additionally, myeloid cell functions (phagocytosis, oxidative burst, and NETosis) were evaluated on fresh cells from patients. Resulting parameters were linked to disease severity and prognosis. Both ICU and non-ICU patients had circulating neutrophils and monocytes with an activated phenotype, as well as elevated concentrations of soluble activation markers (calprotectin, myeloperoxidase, neutrophil extracellular traps, MMP9, sCD14) in their plasma. ICU patients were characterized by increased CD10low CD13low immature neutrophils, LOX-1+ and CCR5+ immunosuppressive neutrophils, and HLA-DRlow CD14low downregulated monocytes. Markers of immature and immunosuppressive neutrophils were strongly associated with severity and poor outcome. Moreover, neutrophils and monocytes of ICU patients had impaired antimicrobial functions, which correlated with organ dysfunction, severe infections, and mortality. Our study reveals a marked dysregulation of innate immunity in COVID-19 patients, which was correlated with severity and prognosis. Together, our results strongly argue in favor of a pivotal role of innate immunity in COVID-19 severe infections and pleads for targeted therapeutic options. One Sentence SummaryOur study reveals a marked dysregulation of innate immunity in COVID-19 patients, which correlates with severity and prognosis.

Antiviral drugs in hospitalized patients with COVID-19 - the DisCoVeRy trial (preprint)

Background: Lopinavir/ritonavir, lopinavir/ritonavir-interferon (IFN)-beta-1a and hydroxychloroquine efficacy for COVID-19 have been evaluated, but detailed evaluation is lacking. Objective: To determine the efficacy of lopinavir/ritonavir, lopinavir/ritonavir-IFN-beta-1a, hydroxychloroquine or remdesivir for improving the clinical, virological outcomes in COVID-19 inpatients. Design: Open-label, randomized, adaptive, controlled trial. Setting: Multi-center trial with patients from France. Participants: 583 COVID-19 inpatients requiring oxygen and/or ventilatory support Intervention: Standard of care (SoC, control), SoC plus lopinavir/ritonavir (400 mg lopinavir and 100 mg ritonavir every 12h for 14 days), SoC plus lopinavir/ritonavir plus IFN-beta-1a (44 micrograms of subcutaneous IFN-beta-1a on days 1, 3, and 6), SoC plus hydroxychloroquine (400 mg twice on day 1 then 400 mg once daily for 9 days) or SoC plus remdesivir (200 mg intravenously on day 1 then 100 mg once-daily for hospitalization duration or 10 days). Measurements: The primary outcome was the clinical status at day 15, measured by the WHO 7-point ordinal scale. Secondary outcomes included SARS-CoV-2 quantification in respiratory specimens and safety analyses. Results: Adjusted Odds Ratio (aOR) for the WHO 7-point ordinal scale were not in favor of investigational treatments: lopinavir/ritonavir versus control, aOR 0.83, 95%CI, 0.55 to 1.26, P=0.39; lopinavir/ritonavir-IFN-beta-1a versus control, aOR 0.69, 95%CI, 0.45 to 1.04, P=0.08; hydroxychloroquine versus control, aOR 0.93, 95%CI, 0.62 to 1.41, P=0.75. No significant effect on SARS-CoV-2 RNA clearance in respiratory tract was evidenced. Lopinavir/ritonavir-containing treatments were significantly associated with more SAE. Limitations: Not a placebo-controlled, no anti-inflammatory agents tested. Conclusion: No improvement of the clinical status at day 15 nor SARS-CoV-2 RNA clearance in respiratory tract specimens by studied drugs. This comforts the recent Solidarity findings. Registration: NCT04315948. Funding: PHRC 2020, Dim OneHealth, REACTing

Sociodemographic Characteristics and Transmission Risk Factors In Patients Hospitalized for COVID-19 Before And During The Lockdown In France (preprint)

Background: The efficacy of lockdown in containing the COVID-19 pandemic has been reported in different studies. However, the impact on sociodemographic characteristics of individuals infected with SARS-CoV-2 has not been evaluated. The aim of this study was to describe the changes in sociodemographic characteristics of patients hospitalized for COVID-19 and to compare the transmission risk factors of COVID-19 before and during lockdown in France. Methods: An observational retrospective study was conducted in a University Hospital in Paris, France. Data from patients hospitalized for COVID-19 in the Infectious Diseases Department between February 26 and May 11, 2020 were collected. The study population was divided into 2 groups: group A of patients infected before lockdown, and group B of patients infected during lockdown, considering a maximum incubation period of 14 days. Sociodemographic characteristics and transmission risk factors were compared between the 2 groups using Student's t-test for continuous variables and Chi-2 test or Fisher exact test for categorical variables.Results: Three hundred eighty-three patients were included in the study, 305 (79.6%) in group A and 78 (20.4%) in group B. Patients in group A were significantly younger (60.0 versus (vs) 66.5 years (p=0.03)). The professionally active population was larger in group A (44.3% vs 24.4%). There were significantly more non-French-speaking people in group B (16.7% vs 6.6%, p<0.01). Most patients from group A had individual accommodation (92.8% vs 74.4%, p<0.01). Contact with a relative was the main transmission risk factor in both groups (24.6% vs 33.3%, p=0.16). Recent travel and large gathering were found only in group A. The proportion of people living in disadvantaged conditions, such as homeless people or people living in social housing, was significantly higher in group B (11.5% vs 4.3%, p=0.03) as was the proportion of institutionalized individuals (14.1% vs 3.0%, p<0.01).Conclusions: In this study conducted in patients hospitalized for COVID-19 in Paris, France, the likelihood of being infected despite the lockdown was higher for people who do not speak French, live in social housing, are homeless or institutionalized. Targeted measures have to be implemented to protect these populations.

CD177, a specific marker of neutrophil activation, is a hallmark of COVID-19 severity and death (preprint)

COVID-19 SARS-CoV-2 infection exhibits wide inter-individual clinical variability, from silent infection to severe disease and death. The identification of high-risk patients is a continuing challenge in routine care. We aimed to identify factors that influence clinical worsening. We analyzed 52 cell populations, 71 analytes, and RNA-seq gene expression in the blood of severe patients from the French COVID cohort upon hospitalization (n = 61). COVID-19 patients showed severe abnormalities of 27 cell populations relative to healthy donors (HDs). Forty-two cytokines, neutrophil chemo-attractants, and inflammatory components were elevated in COVID-19 patients. Supervised gene expression analyses showed differential expression of genes for neutrophil activation, interferon signaling, T- and B-cell receptors, EIF2 signaling, and ICOS-ICOSL pathways in COVID-19 patients. Unsupervised analysis confirmed the prominent role of neutrophil activation, with a high abundance of CD177, a specific neutrophil activation marker. CD177 was the most highly differentially-expressed gene contributing to the clustering of severe patients and its abundance correlated with CD177 protein serum levels. CD177 levels were higher in COVID-19 patients from both the French and "confirmatory" Swiss cohort (n = 203) than in HDs (P< 0.01) and in ICU than non-ICU patients (P< 0.001), correlating with the time to symptoms onset (P = 0.002). Longitudinal measurements showed sustained levels of serum CD177 to discriminate between patients with the worst prognosis, leading to death, and those who recovered (P = 0.01). These results highlight neutrophil activation as a hallmark of severe disease and CD177 assessment as a reliable prognostic marker for routine care.

High-risk exposure without personal protective equipment and infection with SARS-CoV-2 in healthcare workers: results of the CoV-CONTACT prospective cohort (preprint)

Objective: We aimed to estimate the risk of infection in Healthcare workers (HCWs) following a high-risk exposure without personal protective equipment (PPE). Methods: We conducted a prospective cohort in HCWs who had a high-risk exposure to SARS-CoV-2-infected subject without PPE. Daily symptoms were self-reported for 30 days, nasopharyngeal swabs for SARS-CoV-2 RT-PCR were performed at inclusion and at days 3, 5, 7 and 12, SARS-CoV-2 serology was assessed at inclusion and at day 30. Confirmed infection was defined by positive RT-PCR or seroconversion, and possible infection by one general and one specific symptom for two consecutive days. Results: Between February 5th and May 30th, 2020, 154 HCWs were enrolled within 14 days following one high-risk exposure to either a hospital patient (70/154; 46.1%) and/or a colleague (95/154; 62.5%). At day 30, 25.0% had a confirmed infection (37/148; 95%CI, 18.4%; 32.9%), and 43.9% (65/148; 95%CI, 35.9%; 52.3%) had a confirmed or possible infection. Factors independently associated with confirmed or possible SARS-CoV-2 infection were being a pharmacist or administrative assistant rather than being from medical staff (adjusted OR (aOR)=3.8, CI95%=1.3;11.2, p=0.01), and exposure to a SARS-CoV-2-infected patient rather than exposure to a SARS-CoV-2-infected colleague (aOR=2.6, CI95%=1.2;5.9, p=0.02). Among the 26 HCWs with a SARS-CoV-2-positive nasopharyngeal swab, 7 (26.9%) had no symptom at the time of the RT-PCR positivity. Conclusions: The proportion of HCWs with confirmed or possible SARS-CoV-2 infection was high. There were less occurrences of high-risk exposure with patients than with colleagues, but those were associated with an increased risk of infection.

SARS-CoV-2 N-antigenemia: A new alternative to nucleic acid amplification techniques (preprint)

Background. Molecular assays on nasopharyngeal swabs remain the cornerstone of COVID-19 diagnostic. Despite massive worldwide efforts, the high technicalities of nasopharyngeal sampling and molecular assays, as well as scarce resources of reagents, limit our testing capabilities. Several strategies failed, to date, to fully alleviate this testing process (e.g. saliva sampling or antigen testing on nasopharyngeal samples). We assessed the performances of a new ELISA microplate assay quantifying SARS-CoV-2 nucleocapsid antigen (N-antigen) in serum or plasma. Methods. The specificity of the assay, determined on 63 non-COVID patients, was 98.4% (95% confidence interval [CI], 85.3 to 100). Performances were determined on 227 serum samples from 165 patients with RT-PCR confirmed SARS-CoV-2 infection included in the French COVID and CoV-CONTACT cohorts. Findings. Sensitivity was 132/142, 93.0% (95% CI, 84.7 to 100), within the first two weeks after symptoms onset. A subset of 73 COVID-19 patients had a serum collected within 24 hours following or preceding a positive nasopharyngeal swab. Among patients with high nasopharyngeal viral loads, Ct value below 30 and 33, only 1/50 and 4/67 tested negative for N-antigenemia, respectively. Among patients with a negative nasopharyngeal RT-PCR, 8/12 presented positive N-antigenemia. The lower respiratory tract was explored for 6/8 patients, showing positive PCR in 5 cases. Interpretation. This is the first demonstration of the N-antigen antigenemia during COVID-19. Its detection presented a robust sensitivity, especially within the first 14 days after symptoms onset and high nasopharyngeal viral loads. These findings have to be confirmed with higher representation of outpatients. This approach could provide a valuable new option for COVID-19 diagnosis, only requiring a blood draw and easily scalable in all clinical laboratories.

Outcome of SARS-CoV-2 infection linked to MAIT cell activation and cytotoxicity: evidence for an IL-18 dependent mechanism (preprint)

Immune system dysfunction is paramount in Coronavirus disease 2019 (COVID-19) severity and fatality rate. Mucosal-Associated Invariant T (MAIT) cells are innate-like T cells involved in mucosal immunity and protection against viral infections. Here, we studied the immune cell landscape, with emphasis on MAIT cells, in a cohort of 182 patients including patients at various stages of disease activity. A profound decrease of MAIT cell counts in blood of critically ill patients was observed. These cells showed a strongly activated and cytotoxic phenotype that positively correlated with circulating pro-inflammatory cytokines, notably IL-18. MAIT cell alterations markedly correlated with disease severity and patient mortality. SARS-CoV-2-infected macrophages activated MAIT cells in a cytokine-dependent manner involving an IFN-dependent early phase and an IL-18-induced later phase. Therefore, altered MAIT cell phenotypes represent valuable biomarkers of disease severity and their therapeutic manipulation might prevent the inflammatory phase involved in COVID-19 aggravation.

Repurposed prophylaxis strategies for COVID-19: a systematic review (preprint)

Introduction Efficient therapeutic strategies are needed to counter the COVID-19 pandemic, caused by the SARS- CoV-2 virus. In a context where specific vaccines are not yet available, the containment of the pandemic would be facilitated with efficient prophylaxis. Methods We screened several clinical trials repositories and platforms in search of the prophylactic strategies that are investigated against COVID-19 in late April 2020. Results Up to April 27, 2020, we found 68 clinical trials targeting medical workers (n=43, 63%), patients relatives (n=16, 24%) or individuals at risk of severe COVID-19 (n=5, 7%). (Hydroxy)chloroquine was the most frequently evaluated treatment (n=46, 68%), before BCG vaccine (n=5, 7%). Sixty-one (90%) clinical trials were randomized with a median of planned inclusions of 600 (IQR 255-1515). Conclusion The investigated prophylaxis strategies cover both pre- and post-exposure prophylaxis and study numerous immune enhancers and antivirals, although most research efforts are focused on (hydroxy)chloroquine.

Review and methodological analysis of trials currently testing treatment and prevention options for the novel coronavirus disease (COVID-19) globally. (preprint)

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.

SARS-CoV-2 serological analysis of COVID-19 hospitalized patients, pauci-symptomatic individuals and blood donors. (preprint)

It is of paramount importance to evaluate the prevalence of both asymptomatic and symptomatic cases of SARS-CoV-2 infection and their antibody response profile. Here, we performed a pilot study to assess the levels of anti-SARS-CoV-2 antibodies in samples taken from 491 pre- epidemic individuals, 51 patients from Hopital Bichat (Paris), 209 pauci-symptomatic individuals in the French Oise region and 200 contemporary Oise blood donors. Two in-house ELISA assays, that recognize the full-length nucleoprotein (N) or trimeric Spike (S) ectodomain were implemented. We also developed two novel assays: the S-Flow assay, which is based on the recognition of S at the cell surface by flow-cytometry, and the LIPS assay that recognizes diverse antigens (including S1 or N C- terminal domain) by immunoprecipitation. Overall, the results obtained with the four assays were similar, with differences in sensitivity that can be attributed to the technique and the antigen in use. High antibody titers were associated with neutralisation activity, assessed using infectious SARS-CoV- 2 or lentiviral-S pseudotypes. In hospitalized patients, seroconversion and neutralisation occurred on 5-14 days post symptom onset, confirming previous studies. Seropositivity was detected in 29% of pauci-symptomatic individuals within 15 days post-symptoms and 3 % of blood of healthy donors collected in the area of a cluster of COVID cases. Altogether, our assays allow for a broad evaluation of SARS-CoV2 seroprevalence and antibody profiling in different population subsets.

Characterization and treatment of SARS-CoV-2 in nasal and bronchial human airway epithelia (preprint)

In the current COVID-19 pandemic context, proposing and validating effective treatments represents a major challenge. However, the lack of biologically relevant pre-clinical experimental models of SARS-CoV-2 infection as a complement of classic cell lines represents a major barrier for scientific and medical progress. Here, we advantageously used human reconstituted airway epithelial models of nasal or bronchial origin to characterize viral infection kinetics, tissue-level remodeling of the cellular ultrastructure and transcriptional immune signatures induced by SARS-CoV-2. Our results underline the relevance of this model for the preclinical evaluation of antiviral candidates. Foremost, we provide evidence on the antiviral efficacy of remdesivir and the therapeutic potential of the remdesivir-diltiazem combination as a rapidly available option to respond to the current unmet medical need imposed by COVID-19. One Sentence SummaryNew insights on SARS-CoV-2 biology and drug combination therapies against COVID-19.

A brief review of antiviral drugs evaluated in registered clinical trials for COVID-19 (preprint)

Background: Although a number of antiviral agents have been evaluated for coronaviruses there are no approved drugs available. To provide an overview of the landscape of therapeutic research for COVID-19, we conducted a review of registered clinical trials. Methods: A review of currently registered clinical trials was performed on registries, including the Chinese (chictr.org.cn) and US (clinicaltrials.gov) databases to identify relevant studies up to March, 7th 2020. The search was conducted using the search terms "2019-nCoV", "COVID-19", "SARS-CoV-2", "Hcov-19", "new coronavirus", "novel coronavirus". We included interventional clinical trials focusing on patients with COVID-19 and assessing antiviral drugs or agents. Findings: Out of the 353 studies identified, 115 clinical trials were selected for data extraction. Phase IV trials were the most commonly reported study type (n=27, 23%). However, 62 trials (54%) did not describe the phase of the study. Eighty percent (n=92) of the trials were randomized with parallel assignment and the median number of planned inclusions was 63 (IQR, 36-120). Open-label studies were the most frequent (46%) followed by double-blind (13%) and single blind studies (10%). The most frequently assessed therapies were: stem cells therapy (n=23 trials), lopinavir/ritonavir (n=15), chloroquine (n=11), umifenovir (n=9), hydroxychloroquine (n=7), plasma treatment (n=7), favipiravir (n=7), methylprednisolone (n=5), and remdesivir (n=5). Remdesivir was tested in 5 trials with a median of 400 (IQR, 394-453) planned inclusions per trial, while stem cells therapy was tested in 23 trials, but had a median of 40 (IQR, 23-60) planned inclusions per trial. Lopinavir/ritonavir was associated with the highest total number of planned inclusions (2606) followed by remdesivir (2155). Only 52% of the clinical trials reported the treatment dose (n=60) and only 34% (n=39) the duration. The primary outcome was clinical in 76 studies (66%), virological in 27 (23%); radiological in 9 (8%) or immunological in three studies (3%). Interpretation: Numerous clinical trials have been registered since the beginning of the COVID-19 outbreak, however, a number of information regarding drugs or trial design were lacking. Funding: None