Distinct evolution of SARS-CoV-2 Omicron XBB and BA.2.86 lineages combining increased fitness and antibody evasion (preprint)

The unceasing circulation of SARS-CoV-2 leads to the continuous emergence of novel viral sublineages. Here, we isolated and characterized XBB.1, XBB.1.5, XBB.1.9.1, XBB.1.16.1, EG.5.1.1, EG.5.1.3, XBF, BA.2.86.1 and JN.1 variants, representing >80% of circulating variants in November 2023. The XBB subvariants carry few but recurrent mutations in the spike, whereas BA.2.86.1 and JN.1 harbor >30 additional changes. These variants replicated in IGROV-1 but no longer in Vero E6 and were not markedly fusogenic. They potently infected nasal epithelial cells, with EG.5.1.3 exhibiting the highest fitness. Antivirals remained active. Neutralizing antibody (NAb) responses from vaccinees and BA.1/BA.2-infected individuals were markedly lower compared to BA.1, without major differences between variants. An XBB breakthrough infection enhanced NAb responses against both XBB and BA.2.86 variants. JN.1 displayed lower affinity to ACE2 and higher immune evasion properties compared to BA.2.86.1. Thus, while distinct, the evolutionary trajectory of these variants combines increased fitness and antibody evasion.

Determinants of protection against SARS-CoV-2 Omicron BA.1 and Delta infections in fully vaccinated outpatients (preprint)

We aimed to evaluate the association between the humoral and cellular immune responses and symptomatic SARS-CoV-2 infection with Delta or Omicron BA.1 variants in fully vaccinated outpatients. Anti-RBD IgG levels and IFN-{gamma} release were evaluated at PCR-diagnosis of SARS-CoV-2 in 636 samples from negative and positive patients during Delta and Omicron BA.1 periods. Median levels of anti-RBD IgG in positive patients were significantly lower than in negative patients for both variants (p < 0.05). The risk of Delta infection was inversely correlated with anti-RBD IgG titres (aOR = 0.63, 95% CI [0.41; 0.95], p = 0.03) and it was lower in the hybrid immunity group compared to the homologous vaccination group (aOR = 0.22, 95% CI [0.05; 0.62], p = 0.01). In contrast, neither the vaccination scheme nor anti-RBD IgG titers were associated with the risk of BA.1 infection in multivariable analysis. IFN-{gamma} release post-SARS-CoV-2 peptide stimulation was not different between samples from patients infected (either with Delta or Omicron BA.1 variant) or not (p = 0.77). Our results show that high circulating levels of anti-RBD IgG and hybrid immunity were independently associated with a lower risk of symptomatic SARS-CoV-2 infection in outpatients with differences according to the infecting variant.

Long-term humoral response following simultaneous Delta and Omicron BA.1 co-infection (preprint)

To provide insight into the long-term immune response following bivalent vaccines, we sampled vaccinated patients simultaneously co-infected with Delta and BA.1. We reported that simultaneous exposure to the Delta and BA.1 S protein does not confer an additional immune advantage compared to exposure to the Omicron BA.1 S protein alone.

Interactions between Severe Acute Respiratory Syndrome Coronavirus 2 Replication and Major Respiratory Viruses in Human nasal Epithelium.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), along with extensive non-pharmacological interventions, have profoundly altered the epidemiology of major respiratory viruses. Some studies have described virus-virus interactions, particularly manifested by viral interference mechanisms at different scales. Still, our knowledge of the mutual interactions between SARS-CoV-2 and other respiratory viruses remains incomplete. Here, we studied the interactions between SARS-CoV-2 and several respiratory viruses (influenza, RSV, hMPV, and hRV) in a reconstituted human epithelial airway model, exploring different scenarios affecting the sequence and timing of co-infections. We show that the virus type and the sequence of infections are key parameters of virus-virus interactions, having the impact of primary infections on the regulation of the immune response a determinant role in the outcome of secondary infections.

SARS-CoV-2 spike 340 and 337 mutations in Omicron variants are selected after Sotrovimab infusion in immunocompromised patients (preprint)

After monoclonal antibody sotrovimab implementation, Rockett et al have warned on March 9th about two resistant mutations in the spike at position 337 and 340 occurring within the first week in four immunocompromised patients infected by a Delta variant and resulting in viable infection up to 25 days. As sotrovimab is currently the only effective treatment against BA.1 lineage of Omicron variant, we investigated the presence of these mutations in our 22,908 Omicron sequences performed from December 2021 to March 2022. Among 25 Omicron sequences with S:337 and S:340 substitutions, 9 were reported in six patients who had available clinical data and a follow up. All were immunicompromised, and presented a rapid selection of these mutations after sotrovimab monotherapy infusion. With these findings, we underscore that although these mutations are rare, they have been exclusively reported in immunocompromised patients treated with sotrovimab. We urge to consider monoclonal antibody as monotherapy in immunocompromised patients as a risk for escape mutants selection.

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.

Detection and prevalence of SARS-CoV-2 co-infections during the Omicron variant circulation, France, December 2021 - February 2022 (preprint)

In Dec 2021-Feb 2022, an intense and unprecedented co-circulation of SARS-CoV-2 variants with high genetic diversity raised the question of possible co-infections between variants and how to detect them. Using 11 mixes of Delta:Omicron isolates at different ratios, we evaluated the performance of 4 different sets of primers used for whole-genome sequencing and we developed an unbiased bioinformatics method which can detect all co-infections irrespective of the SARS-CoV-2 lineages involved. Applied on 21,387 samples collected between weeks 49-2021 and 08-2022 from random genomic surveillance in France, we detected 53 co-infections between different lineages. The prevalence of Delta and Omicron (BA.1) co-infections and Omicron lineages BA.1 and BA.2 co-infections were estimated at 0.18% and 0.26%, respectively. Among 6,242 hospitalized patients, the intensive care unit (ICU) admission rates were 1.64%, 4.81% and 15.38% in Omicron, Delta and Delta/Omicron patients, respectively. No BA.1/BA.2 co-infections were reported among ICU admitted patients. Although SARS-CoV-2 co-infections were rare in this study, their proper detection is crucial to evaluate their clinical impact and the risk of the emergence of potential recombinants.

Sars-Cov-2 Inactivation by a Panel of Commercialized Buffers and by Traditional Protocols (Heat or SDS) (preprint)

Following the rapid spread of COVID-19 across the globe, the intense response that was demanded of diagnostic centers and research laboratories prompted the use of numerous products and protocols for the management of SARS-CoV-2 specimens. In these settings, proper handling of such infectious specimen is necessary to ensure the safety of personnel and to reduce the risk of active transmission. Our aim was to evaluate the inactivation efficacy of different inactivating methods, notably from commercial lysis buffers available in diagnostic kits. Heat and sodium dodecyl sulfate detergent were also included in our investigations. A cell culture-based assay was used, and supported by molecular qRT-PCR detection, to show in vitro infectivity reduction after inactivation treatment. Overall, all the investigated methods were successful in inactivating SARS-CoV-2. Ten minutes of contact with the commercial buffers completely stopped in vitro SARS-CoV-2 infectivity. Fifteen minutes at 68°C and 30 minutes at 56°C as well as one hour with sodium dodecyl sulfate detergent at 2, 1, 0.5, and 0.1% yielded the same results. These findings demonstrate the reliability of these protocols with regards to biosafety. Inactivation by heat and sodium dodecyl sulfate detergent are rather simple and can be readily available methods for rendering an infectious SARS-CoV-2 specimen inactive, especially in settings where commercial buffers are not available.

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.

Identifying the target population for primary Respiratory Syncytial Virus two-step prevention in infants: Normative Outcome of Hospitalisation Assessment for Newborns (NOHAN) (preprint)

Summary Background Respiratory syncytial virus (RSV) is the leading cause of acute respiratory infection related hospitalisations in infants (RSVh). Most of these infants are younger than 6 months old with no known risk factors. An efficient RSVh prevention program should address both mothers and infants, relying on Non-Pharmaceutical (NPI) and Pharmaceutical Interventions (PI). This study aimed at identifying the target population for these two interventions. Methods Laboratory-confirmed RSV-infected infants hospitalised during the first 6 months of life were enrolled from the Hospices Civils de Lyon birth cohort (2014 to 2018). Clinical variables related to pregnancy and birth (sex, month of birth, birth weight, gestational age, parity) were used for descriptive epidemiology, multivariate logistic regression, and predictive score development. Findings Overall, 616 cases of RSVh in 45 648 infants were identified. Being born before the epidemic season, prematurity, and multiparity were independent predictors of RSVh. Infants born in January or June to August with prematurity and multiparity, and those born in September or December with only one other risk factor (prematurity or multiparity) were identified as moderate-risk, identifying the mothers as candidates for a first level NPI prevention program. Infants born in September or December with prematurity and multiparity, and those born in October or November were identified as high-risk, identifying the mothers and infants as candidates for a second level (NPI and PI) intervention. Interpretation It is possible to determine predictors of RSVh at birth, allowing to enrol early the target population in a two-level RSV prevention intervention. Funding None. Research in context Evidence before this study In infants, the global burden of disease caused by the respiratory syncytial virus (RSV) is increasingly recognised. Nowadays the prevention programs are limited to the only licensed drug, Palivizumab, a humanised monoclonal antibody that shows some benefit in preventing RSV in high-risk infants. With the recent encouraging progress obtained using a maternal vaccine candidate and long half-life monoclonal antibodies administered to newborns, as well as the impact of Covid-19 non-pharmaceutical interventions on the RSV epidemic, there is an urgent need to revisit this prevention paradigm from a much broader perspective. Added value of this study Using a hospital birth cohort (NOHAN strategy) split into a training and a testing dataset, we were able to determine strong maternal and newborn predictors for the risk of RSV hospitalisation. Month of birth, multiparity, and prematurity were sufficient to accurately identify low-, moderate-, and high-risk groups in the validating cohort. Implications of all the available evidence Using the NOHAN strategy, future parents could be enrolled early during pregnancy follow-up in a health-related behaviour change program and then be proposed a vaccine boost for the pregnant women or neutralizing monoclonal antibodies for the newborns. The thresholds for triggering each intervention can be adjusted to the local epidemiology, the resources available, and the evolving evidence concerning the cost-efficiency of the future interventions. Stakeholders, healthcare professionals and policy makers must acknowledge this opportunity when designing the future of RSV prevention programs.

Minimizing school disruption under high incidence conditions due to the Omicron variant in early 2022 (preprint)

As record cases due to the Omicron variant are currently registered in Europe, schools remain a vulnerable setting suffering large disruption. Extending previous modeling of SARS-CoV-2 transmission in schools in France, we estimate that at high incidence rates reactive screening protocols (as currently applied in France) require comparable test resources as weekly screening (as currently applied in some Swiss cantons), for considerably lower control. Our findings can be used to define incidence levels triggering school protocols and optimizing their cost-effectiveness.

SARS-CoV-2 Omicron variant, lineage BA.1, is associated with lower viral load in nasopharyngeal samples compared to Delta variant. (preprint)

High viral load in upper respiratory tract specimens observed for Delta cases may contributed to its increased infectivity compared to the Alpha variant. Herein, we showed that the RT-PCR Ct values in Health Care Workers sampled within five days after symptom onset were significantly higher for Omicron cases than Delta cases (+2.84 Ct, p=0.008). This result comfort the studies showing that the increased transmissibility of Omicron is related to other mechanisms than higher virus excretion.

Investigation of Vaccine Breakthrough Infections by Vaccine strategy during the Delta Variant Wave in France (preprint)

Herein, we describe the characteristics of vaccine breakthrough infections (VBI) in fully vaccinated individuals according to five vaccine strategies during the Delta wave in France. Inclusion criterion was a positive test at least 2 weeks after a full vaccine schedule: homologous vaccination with Pfizer-BioNTech (BNT162b2) or Moderna (mRNA-1273); heterologous vaccination with Astrazeneca and Pfizer-BioNTech (ChadOx1/BNT162b2); single-dose vaccines Johnson & Johnson (Ad26.COV2.S) or Astrazeneca (ChadOx1). A total of 1630 VBI from patients fully vaccinated between February and July were included in this study. SARS-CoV-2 sequencing performed for 1366 samples showed that the delta variant represented 94.1% (1286/1366). Delta-VBI were mainly symptomatic (mild symptoms) with no difference according to the vaccine strategy (p=0.362). The median RT-PCR Ct values at diagnosis were significantly different between symptomatic and asymptomatic cases only for BNT162b2 group (17.7 (15.07, 20.51) vs 19.00 (16.00, 23.00), p=0.004). Up to 50% of VBI was classified as early-VBI (infected less than one month after full immunization) for BNT162b2, mRNA-1273, ChadOx1, and J Ad26.COV2.S. People aged 14-49 yo were overrepresented in early VBI compared to non-early VBI for BNT162b2 and mRNA-1273 (73.92% vs 37.87% for BNT162b2 and 77.78% vs 46.67 % for mRNA-1273, p<0.05). Our data emphasize a high prevalence of Delta-VBI occurring only one month after full immunization in young patients that might be related to relaxation of barrier gestures.

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.

Immunogenicity and efficacy of heterologous ChadOx1/BNT162b2 vaccination (preprint)

Following severe adverse reactions in patients vaccinated with the AstraZeneca ChadOx1 (Chad) vaccine, European health authorities have recommended that patients under the age of 55 who received one dose of Chad vaccine receive a second dose of Pfizer BNT162b2 (BNT) vaccine as a booster. However, the effectiveness and the immunogenicity of this vaccination regimen have not been formally tested. Here, we show that the heterologous Chad/BNT combination confers better protection against SARS-CoV-2 infection than the homologous BNT/BNT combination in a population of health care workers. To understand the underlying mechanism, we monitored in a longitudinal way the anti-spike immunity conferred by each vaccinal combination. Both combinations induced strong anti-spike antibody responses after boost in all vaccinated individuals. However, sera from heterologous vaccinated individuals displayed a stronger neutralizing activity, regardless of the SARS-CoV-2 variant analyzed, and this was associated with more switched memory RBD-specific B cells with an activated phenotype and less IgA. The Chad vaccine induced a stronger T cell response than the BNT vaccine after the priming dose, and the reciprocal was true for the IgG response, which could explain the complementarity of both vaccines when used in an heterologous setting. This strongly protective vaccination regimen could be therefore particularly suitable for immunocompromised individuals.

Impact of B.1.351 (beta) SARS-CoV-2 variant on BNT162b2 mRNA vaccine effectiveness in long-term care facilities of eastern France: a retrospective cohort study (preprint)

Background We aimed to assess the effectiveness of the BNT162b2 mRNA vaccine against B.1.351 (beta) variant among residents of long-term care facilities (LCTFs) in eastern France. Methods We used routinely collected surveillance and COVID-19 vaccination data to conduct a retrospective cohort study of SARS-CoV-2 B.1.351 infection incidence and vaccine effectiveness among LCTFs residents in eastern France between 15 January and 19 May 2021. Data from secondary RT-PCR screening were used to identify B.1.351 variants. Findings Included in our analysis were 378 residents from five LCTFs: 287 (76%) females, with median (IQR) age of 89 (83-92) years. Two B.1.351 outbreaks took place in LTCFs in which more than 70% of residents had received two doses of BNT162b2 mRNA vaccine, which included 11 cases of severe disease and six deaths among those who had received two doses. Vaccine effectiveness (95% CI) seven days after the second dose of vaccine was 49% (14-69) against any infection with B.1.351 and 86% (67-94) against severe forms of COVID-19. In multivariable analysis, females were less likely to develop severe forms of disease (IRR = 0.35, 95% CI = 0.20-0.63). Interpretation We observed reduced vaccine effectiveness associated with B.1.351, as well as B.1.351 outbreaks in two LTCFs among individuals who had received two doses of vaccine. Our findings highlight the need to maintain SARS-CoV-2 surveillance in these high-risk settings beyond the current COVID-19 mass vaccination campaign, and advocate for a booster vaccine dose prior to the next winter season.

Immunity to SARS-CoV-2 in a Dialyzed Patient Who Developed COVID-19 Twenty Days After the Second Dose of BNT162b2 Vaccine: a Case Report (preprint)

Introduction: End stage kidney disease (ESKD) and cancer have been identified as risk factors for severe and fatal cases of COVID-19, making vaccination in these patients a priority. Patients suffering from ESKD have a significantly weaker response to common vaccines than general population. However, humoral and cellular immune responses after two doses of RNA-based vaccine BNT162b2 (Pfizer–BioNTech) have been poorly explored in this vulnerable population.Case presentationA 69-year-old male patient was followed for ESKD and myeloma. He developed a severe SARS-CoV-2 pneumonia twenty days after two doses of BNT162b2 vaccine. Whole genome sequencing found that the virus belonged to the 20I/501Y.V1 clade. A serology draws eight days after the 2 nd vaccine dose showed positive RBD IgG without neutralizing activity. A serum specimen sampled thirty days after the onset of SARS-CoV-2 infection showed seroconversion against both RBD and N antigens. This specimen was shown to exhibit a frank neutralizing activity. The QuantiFERON® SARS-CoV-2 (Qiagen) showed a positive specific cellular response although the QuantiFERON monitor displayed a weak cellular response. ConclusionsImpaired immunity due to renal failure probably explain the severe pneumonia despite vaccination. The fact that the patient developpe a neutralizing activity and a cellular response after a third stimulation by infection may suggest to systemically administrate a third dose of vaccine in ESKD patients.

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.

Live virus neutralization testing in convalescent and vaccinated subjects against 19A, 20B, 20I/501Y.V1 and 20H/501.V2 isolates of SARS-CoV-2 (preprint)

Background: SARS-CoV-2 mutations appeared recently and can lead to conformational changes in the spike protein and probably induce modifications in antigenicity. In this study, we wanted to assess the neutralizing capacity of antibodies to prevent cell infection, using a live virus neutralisation test. Methods: Sera samples were collected from different populations: two-dose vaccinated COVID-19-naive healthcare workers (HCWs; Pfizer-BioNTech BNT161b2), 6-months post mild COVID-19 HCWs, and critical COVID-19 patients. We tested various clades such as 19A (initial one), 20B (B.1.1.241 lineage), 20I/501Y.V1 (B.1.1.7 lineage), and 20H/501Y.V2 (B.1.351 lineage). Results: No significant difference was observed between the 20B and 19A isolates for HCWs with mild COVID-19 and critical patients. However, a significant decrease in neutralisation ability was found for 20I/501Y.V1 in comparison with 19A isolate for critical patients and HCWs 6-months post infection. Concerning 20H/501Y.V2, all populations had a significant reduction in neutralising antibody titres in comparison with the 19A isolate. Interestingly, a significant difference in neutralisation capacity was observed for vaccinated HCWs between the two variants whereas it was not significant for the convalescent groups. Conclusion: Neutralisation capacity was slightly reduced for critical patients and HCWs 6-months post infection. No neutralisation escape could be feared concerning the two variants of concern in both populations. The reduced neutralising response observed towards the 20H/501Y.V2 in comparison with the 19A and 20I/501Y.V1 isolates in fully immunized subjects with the BNT162b2 vaccine is a striking finding of the study.

Epidemiological and clinical insights from SARS-CoV-2 RT-PCR cycle amplification values (preprint)

The SARS-CoV-2 pandemic has led to an unprecedented daily use of molecular RT-PCR tests. These tests are interpreted qualitatively for diagnosis, and the relevance of the test result intensity, i.e. the number of amplification cycles (Ct), is debated because of strong potential biases. We analyze a national database of tests performed on more than 2 million individuals between January and November 2020. Although we find Ct values to vary depending on the testing laboratory or the assay used, we detect strong significant trends with patient age, number of days after symptoms onset, or the state of the epidemic (the temporal reproduction number) at the time of the test. These results suggest that Ct values can be used to improve short-term predictions for epidemic surveillance.