ABSTRACT
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.
ABSTRACT
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.
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BackgroundThe 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. MethodsIn 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. FindingsBetween 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). InterpretationRemdesivir use for the treatment of hospitalised patients with COVID-19 was not associated with clinical improvement at day 15. FundingEuropean 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.
ABSTRACT
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.
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ObjectivesWe evaluated the clinical, virological and safety outcomes of lopinavir/ritonavir, lopinavir/ritonavir-interferon (IFN)-{beta}-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. MethodsWe 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. ResultsThe intention-to-treat population included 593 participants (lopinavir/ritonavir, n=147; lopinavir/ritonavir-IFN-{beta}-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-{beta}-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. ConclusionIn adults hospitalized for COVID-19, lopinavir/ritonavir, lopinavir/ritonavir-IFN-{beta}-1a and hydroxychloroquine did not improve the clinical status at day 15, nor SARS-CoV-2 clearance in respiratory tract specimens.
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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.
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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.
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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.
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Schools were closed extensively in 2020-2021 to counter COVID-19 spread, impacting students education and well-being. With highly contagious variants expanding in Europe, 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 in a primary and a secondary school, and data from pilot screenings in 683 schools during the 2021 spring Alpha wave in France. We fitted the model to observed school prevalence to estimate the school-specific reproductive number and performed a cost-benefit analysis examining different intervention protocols. We estimated RAlpha=1.40 (95%CI 1.35-1.45) in the primary and RAlpha=1.46 (1.41-1.51) in the secondary school during the wave, higher than Rt estimated from community surveillance. Considering the Delta variant and vaccination coverage in Europe, we estimated RDelta=1.66 (1.60-1.71) and RDelta=1.10 (1.06-1.14) in the two settings, respectively. Under these conditions, weekly screening with 75% adherence would reduce cases by 34% (95%CI 32-36%) in the primary and 36% (35-39%) in the secondary school compared to symptom-based testing. Insufficient adherence was recorded in pilot screening (median [≤]53%). Regular screening would also reduce student-days lost up to 80% compared to reactive closure. Moderate vaccination coverage in students would still benefit from regular screening for additional control (23% case reduction with 50% vaccinated children). COVID-19 pandemic will likely continue to pose a risk for school opening. Extending vaccination coverage in students, complemented by regular testing largely incentivizing adherence, are essential steps to keep schools open, especially under the threat of more contagious variants.
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BackgroundWe 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. MethodsWe 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. FindingsIncluded 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). InterpretationWe 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.
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BackgroundSARS-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. MethodsSera 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). ResultsNo 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. ConclusionNeutralisation 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.
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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.
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BackgroundLopinavir/ritonavir, lopinavir/ritonavir-interferon (IFN)-{beta}-1a and hydroxychloroquine efficacy for COVID-19 have been evaluated, but detailed evaluation is lacking. ObjectiveTo determine the efficacy of lopinavir/ritonavir, lopinavir/ritonavir-IFN-{beta}-1a, hydroxychloroquine or remdesivir for improving the clinical, virological outcomes in COVID-19 inpatients. DesignOpen-label, randomized, adaptive, controlled trial. SettingMulti-center trial with patients from France. Participants583 COVID-19 inpatients requiring oxygen and/or ventilatory support InterventionStandard 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 g 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). MeasurementsThe 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. ResultsAdjusted 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. LimitationsNot a placebo-controlled, no anti-inflammatory agents tested. ConclusionNo 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. RegistrationNCT04315948. FundingPHRC 2020, Dim OneHealth, REACTing
ABSTRACT
We conducted a prospective study in healthcare workers (n=296) of the University Hospital of Lyon, France. Serum samples (n=296) collected six months after disease onset were tested using three commercial assays: the Wantai Ab assay detecting total antibodies against the receptor binding domain (RBD) of the S protein, the bioMerieux Vidas assay detecting IgG to the RBD and the Abbott Architect assay detecting IgG to the N protein. The neutralising antibody (NAb) titre was also determined for all samples with a virus neutralisation assay (VNA) using live virus. The positivity rate was 100% with the Wantai assay, 84.8% with the bioMerieux assay and 55.4% with the Abbott assay. Only 51% of HCWs were positive for the presence of NAb. Less than 10 % of HCWs had a NAb titre greater than 80. At a neutralising titre of 80, the area under the curves [IC 95%] was 0.71 [0.62-0.81], 0.75 [0.65-0.85] and 0.95 [0.92-0.97] for Wantai, Abbott and Vidas respectively. The data presented herein suggest that commercial assays detecting antibodies against the N protein must not be used in long-term seroprevalence surveys while the Wantai assay could be useful for this purpose. VNA should remain the gold standard to assess the protective antibody response, but some commercial assays could be used as first-line screening of long-term presence of NAb.
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We report the implementation of a two-step strategy for the identification of SARS-CoV-2 variants carrying the spike deletion H69-V70 ({Delta}H69/{Delta}V70). This spike deletion resulted in a S-gene target failure (SGTF) of a three-target RT-PCR assay (TaqPath kit). Whole genome sequencing performed on 37 samples with SGTF revealed several receptor-binding domain mutations co-occurring with {Delta}H69/{Delta}V70. More importantly, this strategy enabled the first detection of the variant of concern 202012/01 in France on December 21th 2020. Since September a SARS-CoV-2 spike (S) deletion H69-V70 ({Delta}H69/{Delta}V70) has attracted increasing attention. This deletion was detected in the cluster-5 variant identified both in minks and humans in Denmark. This cluster-5 variant carries a receptor binding domain (RBD) mutation Y453F and was associated with reduced susceptibility to neutralizing antibodies to sera from recovered COVID-19 patients [1-3]. The {Delta}H69/{Delta}V70 has also co-occurred with two other RBD mutations of increasing interest [4]: N439K that is currently spreading in Europe and might also have reduced susceptibility to SARS-CoV-2 antibodies [5]; and N501Y that is part of the SARS-CoV-2 variant of concern (VOC) 202012/01 recently detected in England [6]. Although the impact of {Delta}H69/{Delta}V70 on SARS-CoV-2 pathogenesis is not clear, enhanced surveillance is urgently needed. Herein we report the implementation of a two-step strategy enabling a rapid detection of VOC 202012/01 or other variants carrying {Delta}H69/{Delta}V70.
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BackgroundA comprehensive assessment of COVID-19 in healthcare workers (HCWs) including the investigation of viral shedding duration is critical. MethodsA longitudinal study including 319 HCWs was conducted. After SARS-CoV-2 screening with RT-PCR assay, other respiratory pathogens were tested with a multiplex molecular panel. For SARS-CoV-2 positive HCWs, the normalized viral load was determined weekly; viral culture and virus neutralization assays were also performed. For 190 HCWs tested negative, SARS-CoV-2 serological testing was performed one month after the inclusion. FindingsOf the 319 HCWs included, 67 (21.0%) were tested positive for SARS-CoV-2; two of them developed severe COVID-19. The proportion of smell and taste dysfunction was significantly higher in SARS-CoV-2 positive HCWs than in negative ones (38.8% vs 9.5% and 37.3% vs 10.7%, respectively, p<0.001). Of the 67 positive patients, 9.1% were tested positive for at least another respiratory pathogen (vs 19.5%, p=0.07). The proportion of HCWs with a viral load > 5.0 log10 cp/ml (Ct value <25) was less than 15% at 8 days after symptom onset; 12% of them were still positive after 40 days (Ct >37). More than 90% of culturable virus had a viral load > 4.5 log10 cp/ml (Ct < 26) and were collected within 10 days after symptom onset. From HCWs tested negative, 6/190 (3.2%) exhibited seroconversion for IgG antibodies. InterpretationOur data suggest that the determination of normalized viral load (or its estimation through Ct values) can be useful for discontinuing isolation of HCWs and facilitating their safe return to work. HCWs presenting mild COVID-19 are unlikely infectious 10 days after symptom onset. FundingFondation des Hospices Civils de Lyon. bioMerieux provided diagnostic kits.
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ObjectivesWe evaluated widely-used SARS-CoV-2 serological tests and their potential association with virus neutralization test (VNT) in a cohort of mild COVID-19 patients. MethodsA total of 439 specimens were longitudinally collected from 76 healthcare workers with RT-PCR-confirmed mild COVID-19. Nine serological assays developed by leading global companies (Abbott, DiaSorin, Siemens, Bio-Rad, Wantai, bioMerieux, Euroimmun) were assessed. For each test the sensitivity to detect SARS-CoV-2 antibodies was determined weekly after symptom onset. Correlation and concordance were assessed using the Spearman and Cohens Kappa coefficients, respectively. Positive percent agreement and negative percent agreement (NPA) with the VNT were also determined. ResultsThe Wantai Total Ab assay targeting the receptor binding domain (RBD) within the S protein presented the best sensitivity at different times during the course of disease. The best correlation between antibody level and neutralizing antibody titer was found with the Euroimmun S1-based IgA assay (Spearman coefficient [95%CI]: 0.71 [0.61-0.79]). A moderate concordance (Kappa [95%CI]: 0.43[0.23-0.63]) as well as the lowest NPA (33%) was found between the Wantai Total Ab assay and the VNT. Compared to the Wantai Total Ab assay, other total Ab or IgG assays targeting the S or the RBD (bioMerieux, DiaSorin, Siemens,) were more concordant with the VNT (Kappa>0.7 for the three tests) and had a higher NPA (range: 90% to 97%). ConclusionsAlthough some assays presented a better concordance with VNT than others, the present findings emphasize that commercialized serological tests including those targeting the RBD cannot substitute VNT for the assessment of functional antibody response.
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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.
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As in past pandemics, co-circulating pathogens may play a role in the epidemiology of coronavirus disease 2019 (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARSCoV-2). Here we hypothesized that influenza interacted with SARS-CoV-2 during the early 2020 epidemic of COVID-19 in Europe. We developed a population-based model of SARS-CoV-2 transmission, combined with mortality incidence data in four European countries, to test a range of assumptions about the impact of influenza. We found consistent evidence for a 2-2.5-fold population-level increase in SARSCoV-2 transmission associated with influenza during the period of co-circulation. These results suggest the need to increase vaccination against influenza, not only to reduce the burden due to influenza viruses, but also to counteract their facilitatory impact on SARS-CoV-2.
ABSTRACT
Through routine genomic surveillance of the novel SARS-CoV-2 virus (n=229 whole genome sequences), 2 different frameshifting deletions were newly detected in the open reading frame (ORF) 6, starting at the same position (27267). While the 26-nucleotide deletion variant was only found in one sample in March 2020, the 34-nucleotide deletion variant was found within a single geriatric hospital unit in 5/9 patients sequenced and one health care worker with samples collected between April 2nd and 9th, 2020. Both the presence of the 34-nucleotide deletion variant limited to this unit and the clustering of the corresponding whole genome sequences by phylogeny analysis strongly suggested a nosocomial transmission between patients. Interestingly, prolonged viral excretion of the 34-nucleotide deletion variant was identified in a stool sample 14 days after initial diagnosis for one patient. Clinical data revealed no significant difference in disease severity between patients harboring the wild-type or the 34-nucleotide deletion variants. The in vitro infection of the two deletion variants on primate endothelial kidney cells (BGM) and human lung adenocarcinoma cells (Calu-3) yielded comparable replication kinetics with the wild-type strain. Furthermore, high viral loads were found in vivo regardless of the presence or absence of the ORF6 deletion. Our study highlights the transmission and replication capacity of two newly described deletion variants in the same ORF6 region. ImportanceWhile the SARS-CoV-2 genome has remained relatively stable since its emergence in the human population, genomic deletions are an evolutionary pattern previously described for the related SARS-CoV. Real-time genomic monitoring of the circulating variants is paramount to detect strain prevalence and transmission dynamics. Given the role of ORF6 in interferon modulation, further characterization, such as mechanistic interactions and interferon monitoring in patients, is crucial in understanding the viral-host factors driving disease evolution.
