Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 12 de 12
Filter
2.
PLoS Med ; 19(3): e1003922, 2022 03.
Article in English | MEDLINE | ID: covidwho-1714706

ABSTRACT

BACKGROUND: The risk of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) transmission through corneal graft is an ongoing debate and leads to strict restrictions in corneas procurement, leading to a major decrease in eye banking activity. The aims of this study are to specifically assess the capacity of human cornea to be infected by SARS-CoV-2 and promote its replication ex vivo, and to evaluate the real-life risk of corneal contamination by detecting SARS-CoV-2 RNA in corneas retrieved in donors diagnosed with Coronavirus Disease 2019 (COVID-19) and nonaffected donors. METHODS AND FINDINGS: To assess the capacity of human cornea to be infected by SARS-CoV-2, the expression pattern of SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE-2) and activators TMPRSS2 and Cathepsins B and L in ocular surface tissues from nonaffected donors was explored by immunohistochemistry (n = 10 corneas, 78 ± 11 years, 40% female) and qPCR (n = 5 corneas, 80 ± 12 years, 40% female). Additionally, 5 freshly excised corneas (80 ± 12 years, 40% female) were infected ex vivo with highly concentrated SARS-CoV-2 solution (106 median tissue culture infectious dose (TCID50)/mL). Viral RNA was extracted from tissues and culture media and quantified by reverse transcription quantitative PCR (RT-qPCR) (viral RNA copies) 30 minutes (H0) and 24 hours (H24) after infection. To assess the risk of corneal contamination by SARS-CoV-2, viral RNA was tested by RT-qPCR (Ct value) in both corneas and organ culture media from 14 donors diagnosed with COVID-19 (74 ± 10 years, 29% female) and 26 healthy donors (79 ± 13 years, 57% female), and in organ culture media only from 133 consecutive nonaffected donors from 2 eye banks (73 ± 13 years, 29% female). The expression of receptor and activators was variable among samples at both protein and mRNA level. Based on immunohistochemistry findings, ACE-2 was localized mainly in the most superficial epithelial cells of peripheral cornea, limbus, and conjunctiva, whereas TMPRSS2 was mostly expressed in all layers of bulbar conjunctiva. A significant increase in total and positive strands of IP4 RNA sequence (RdRp viral gene) was observed from 30 minutes to 24 hours postinfection in central cornea (1.1 × 108 [95% CI: 6.4 × 107 to 2.4 × 108] to 3.0 × 109 [1.4 × 109 to 5.3 × 109], p = 0.0039 and 2.2 × 107 [1.4 × 107 to 3.6 × 107] to 5.1 × 107 [2.9 × 107 to 7.5 × 107], p = 0.0117, respectively) and in corneoscleral rim (4.5 × 109 [2.7 × 109 to 9.6 × 109] to 3.9 × 1010 [2.6 × 1010 to 4.4 × 1010], p = 0.0039 and 3.1 × 108 [1.2 × 108 to 5.3 × 108] to 7.8 × 108 [3.9 × 108 to 9.9 × 108], p = 0.0391, respectively). Viral RNA copies in ex vivo corneas were highly variable from one donor to another. Finally, viral RNA was detected in 3 out of 28 corneas (11%) from donors diagnosed with COVID-19. All samples from the 159 nonaffected donors were negative for SARS-CoV-2 RNA. The main limitation of this study relates to the limited sample size, due to limited access to donors diagnosed with COVID-19 and concomitant decrease in the procurement corneas from nonaffected donors. CONCLUSIONS: In this study, we observed the expression of SARS-CoV-2 receptors and activators at the human ocular surface and a variable increase in viral RNA copies 24 hours after experimental infection of freshly excised human corneas. We also found viral RNA only in a very limited percentage of donors with positive nasopharyngeal PCR. The low rate of positivity in donors diagnosed with COVID-19 calls into question the utility of donor selection algorithms. TRIAL REGISTRATION: Agence de la Biomédecine, PFS-20-011 https://www.agence-biomedecine.fr/.


Subject(s)
COVID-19/complications , Cornea/virology , Corneal Diseases/virology , Eye Infections, Viral/virology , SARS-CoV-2/physiology , Adult , Aged , Angiotensin-Converting Enzyme 2/metabolism , Animals , Cathepsins/metabolism , Chlorocebus aethiops , Cornea/metabolism , Culture Media , Female , Humans , Male , Middle Aged , Organ Culture Techniques , RNA, Viral/metabolism , Receptors, Coronavirus/metabolism , Serine Endopeptidases/metabolism , Vero Cells , Virus Replication
3.
Euro Surveill ; 27(6)2022 Feb.
Article in English | MEDLINE | ID: covidwho-1686391

ABSTRACT

BackgroundThe COVID-19 pandemic has led to an unprecedented daily use of RT-PCR tests. These tests are interpreted qualitatively for diagnosis, and the relevance of the test result intensity, i.e. the number of quantification cycles (Cq), is debated because of strong potential biases.AimWe explored the possibility to use Cq values from SARS-CoV-2 screening tests to better understand the spread of an epidemic and to better understand the biology of the infection.MethodsWe used linear regression models to analyse a large database of 793,479 Cq values from tests performed on more than 2 million samples between 21 January and 30 November 2020, i.e. the first two pandemic waves. We performed time series analysis using autoregressive integrated moving average (ARIMA) models to estimate whether Cq data information improves short-term predictions of epidemiological dynamics.ResultsAlthough we found that the Cq values varied depending on the testing laboratory or the assay used, we detected strong significant trends associated 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. Furthermore, knowing the quartiles of the Cq distribution greatly reduced the error in predicting the temporal reproduction number of the COVID-19 epidemic.ConclusionOur results suggest that Cq values of screening tests performed in the general population generate testable hypotheses and help improve short-term predictions for epidemic surveillance.


Subject(s)
COVID-19 , SARS-CoV-2 , France/epidemiology , Humans , Pandemics , Reverse Transcriptase Polymerase Chain Reaction
4.
Clin Microbiol Infect ; 28(5): 734.e1-734.e6, 2022 May.
Article in English | MEDLINE | ID: covidwho-1683015

ABSTRACT

OBJECTIVES: This study aimed to evaluate the immunochromatographic coronavirus disease 2019 (COVID-19) speed antigen test (BioSpeedia, France) as an antigen point-of-care test (AgPOCT) to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection at the paediatric emergency department of the University Hospital of Saint-Etienne in France. METHODS: Between 15 January and 28 May, 2021, children presenting with respiratory symptoms compatible with COVID-19 infection (symptomatic group) or those requiring hospitalization for any reason (asymptomatic group) were included prospectively and received a nasopharyngeal aspiration to carry out both AgPOCT and quantitative reverse transcription (RT) PCR (RT-qPCR) tests, with the latter being used as the reference standard, for the diagnosis of SARS-CoV-2 infection. RESULTS: Among the 1009 enrolled children, we obtained a result from both techniques for 990: 33 (3.3%) tested positive with AgPOCT and 46 (4.6%) with RT-qPCR. The overall sensitivity and specificity of the AgPOCT were 69.6% (95% confidence interval (CI), 54.3-82.3) and 99.9% (95% CI, 99.4-100), respectively, compared with the RT-qPCR. Sensitivity increased to 82.9% (95% CI, 66.4-93.4) in symptomatic children. The mean cycle threshold value was significantly lower in positive samples for AgPOCT than in negative samples in the overall population and in both the symptomatic and asymptomatic groups. DISCUSSION: The use of the COVID-19 speed antigen test at the bedside in the emergency department has satisfactory performance for diagnosing SARS-CoV-2 infection in symptomatic children.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , COVID-19 Testing , Child , Emergency Service, Hospital , Humans , Point-of-Care Systems , Sensitivity and Specificity
5.
2021.
Preprint in English | Other preprints | ID: ppcovidwho-294824

ABSTRACT

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-naïve 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.

6.
Emerg Microbes Infect ; 10(1): 1499-1502, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1337230

ABSTRACT

SARS-CoV-2 mutations appeared recently and can lead to conformational changes in the spike protein and probably induce modifications in antigenicity. We assessed the neutralizing capacity of antibodies to prevent cell infection, using a live virus neutralization test with different strains [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)] in serum samples 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. 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 neutralization 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 neutralizing antibody titers in comparison with the 19A isolate. Interestingly, a significant difference in neutralization capacity was observed for vaccinated HCWs between the two variants but not in the convalescent groups.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , SARS-CoV-2/immunology , COVID-19/prevention & control , COVID-19/virology , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/genetics , Humans , Neutralization Tests , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification
7.
Euro Surveill ; 26(29)2021 07.
Article in English | MEDLINE | ID: covidwho-1321641

ABSTRACT

The Rhône-Loire metropolitan areas' 2020/21 respiratory syncytial virus (RSV) epidemic was delayed following the implementation of non-pharmaceutical interventions (NPI), compared with previous seasons. Very severe lower respiratory tract infection incidence among infants ≤ 3 months decreased twofold, the proportion of cases among children aged > 3 months to 5 years increased, and cases among adults > 65 years were markedly reduced. NPI appeared to reduce the RSV burden among at-risk groups, and should be promoted to minimise impact of future RSV outbreaks.


Subject(s)
Epidemics , Respiratory Syncytial Virus Infections , Respiratory Syncytial Virus, Human , Respiratory Tract Infections , Adult , Child , France/epidemiology , Hospitalization , Humans , Infant , Respiratory Syncytial Virus Infections/epidemiology , Respiratory Syncytial Virus Infections/prevention & control , Respiratory Tract Infections/epidemiology
8.
J Trace Elem Med Biol ; 68: 126818, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1300926

ABSTRACT

CONTEXT: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that emerged late in 2019 is the etiologic agent of coronavirus disease 2019 (Covid-19). There is an urgent need to develop curative and preventive therapeutics to limit the current pandemic and to prevent the re-emergence of Covid-19. This study aimed to assess the in vitro activity of copper gluconate against SARS-CoV-2. METHODS: Vero E6 cells were cultured with or without copper gluconate 18-24 hours before infection. Cells were infected with a recombinant GFP expressing SARS-CoV-2. Cells were infected with a recombinant GFP expressing SARS-CoV-2. Infected cells were incubated in fresh medium containing varying concentration of copper gluconate (supplemented with bovine serum albumin or not) for an additional 48 -h period. The infection level was measured by the confocal microscopy-based high content screening method. The cell viability in presence of copper gluconate was assessed by XTT and propidium iodide assays. RESULTS: The viability of Vero E6 cells exposed to copper gluconate up to 200 µM was found to be similar to that of unexposed cells, but it dropped below 70 % with 400 µM of this agent after 72 h of continuous exposure. The infection rate was 23.8 %, 18.9 %, 20.6 %, 6.9 %, 5.3 % and 5.2 % in cells treated prior infection with 0, 2, 10, 25, 50 and 100 µM of copper gluconate respectively. As compared to untreated cells, the number of infected cells was reduced by 71 %, 77 %, and 78 % with 25, 50, and 100 µM of copper gluconate respectively (p < 0.05). In cells treated only post-infection, the rate of infection dropped by 73 % with 100 µM of copper gluconate (p < 0.05). However, the antiviral activity of copper gluconate was abolished by the addition of bovine serum albumin. CONCLUSION: Copper gluconate was found to mitigate SARS-CoV-2 infection in Vero E6 cells but this effect was abolished by albumin, which suggests that copper will not retain its activity in serum. Furthers studies are needed to investigate whether copper gluconate could be of benefit in mucosal administration such as mouthwash, nasal spray or aerosols.


Subject(s)
Gluconates/pharmacology , Microscopy, Confocal , SARS-CoV-2/drug effects , Animals , Antiviral Agents/pharmacology , COVID-19/pathology , COVID-19/virology , Cell Survival/drug effects , Chlorocebus aethiops , Green Fluorescent Proteins/metabolism , Vero Cells
9.
J Clin Microbiol ; 59(2)2021 01 21.
Article in English | MEDLINE | ID: covidwho-1066814

ABSTRACT

This study assessed the diagnostic performance of the new COVID19SEROSpeed IgM/IgG rapid test (BioSpeedia, a spinoff of the Pasteur Institute of Paris) for the detection of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in comparison to other commercial antibody assays through a large cross-European investigation. The clinical specificity was assessed on 215 prepandemic sera (including some from patients with viral infections or autoimmune disorders). The clinical sensitivity was evaluated on 710 sera from 564 patients whose SARS-CoV-2 infection was confirmed by quantitative reverse transcription-PCR (qRT-PCR) and whose antibody response was compared to that measured by five other commercial tests. The kinetics of the antibody response were also analyzed in seven symptomatic patients. The specificity of the test (BioS) on prepandemic specimens was 98.1% (95% confidence interval [CI], 96.2% to 99.4%). When tested on the 710 pandemic specimens, BioS showed an overall clinical sensitivity of 86.0% (95% CI, 0.83 to 0.89), with good concordance with the Euroimmun assay (overall concordance of 0.91; Cohen's kappa coefficient of 0.62). Due in part to simultaneous detection of IgM and IgG for both S1 and N proteins, BioS exhibited the highest positive percent agreement at ≥11 days post-symptom onset (PSO). In conclusion, the BioS IgM/IgG rapid test was highly specific and demonstrated a higher positive percentage of agreement than all the enzyme-linked immunosorbent assay/chemiluminescence immunoassay (ELISA/CLIA) commercial tests considered in this study. Moreover, by detecting the presence of antibodies prior to 11 days PSO in 78.2% of the patients, the BioS test increased the efficiency of the diagnosis of SARS-CoV-2 infection in the early stages of the disease.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19/diagnosis , Immunoassay/methods , SARS-CoV-2/isolation & purification , Antibodies, Viral/blood , Antigens, Viral/immunology , COVID-19/blood , COVID-19/pathology , Chromatography, Affinity , Europe , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Kinetics , SARS-CoV-2/immunology , Sensitivity and Specificity , Time Factors
10.
Cell Mol Immunol ; 18(2): 318-327, 2021 02.
Article in English | MEDLINE | ID: covidwho-1060623

ABSTRACT

Understanding the immune responses elicited by SARS-CoV-2 infection is critical in terms of protection against reinfection and, thus, for public health policy and vaccine development for COVID-19. In this study, using either live SARS-CoV-2 particles or retroviruses pseudotyped with the SARS-CoV-2 S viral surface protein (Spike), we studied the neutralizing antibody (nAb) response in serum samples from a cohort of 140 SARS-CoV-2 qPCR-confirmed infections, including patients with mild symptoms and also more severe forms, including those that required intensive care. We show that nAb titers correlated strongly with disease severity and with anti-spike IgG levels. Indeed, patients from intensive care units exhibited high nAb titers; conversely, patients with milder disease symptoms had heterogeneous nAb titers, and asymptomatic or exclusive outpatient-care patients had no or low nAbs. We found that nAb activity in SARS-CoV-2-infected patients displayed a relatively rapid decline after recovery compared to individuals infected with other coronaviruses. Moreover, we found an absence of cross-neutralization between endemic coronaviruses and SARS-CoV-2, indicating that previous infection by human coronaviruses may not generate protective nAbs against SARS-CoV-2. Finally, we found that the D614G mutation in the spike protein, which has recently been identified as the current major variant in Europe, does not allow neutralization escape. Altogether, our results contribute to our understanding of the immune correlates of SARS-CoV-2-induced disease, and rapid evaluation of the role of the humoral response in the pathogenesis of SARS-CoV-2 is warranted.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19 Serological Testing , COVID-19/immunology , COVID-19/pathology , SARS-CoV-2/immunology , Severity of Illness Index , Adult , Aged , Aged, 80 and over , Amino Acid Substitution , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/blood , COVID-19/virology , Female , Humans , Kinetics , Longitudinal Studies , Male , Middle Aged , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
11.
Cell Mol Immunol ; 18(2): 318-327, 2021 02.
Article in English | MEDLINE | ID: covidwho-1012680

ABSTRACT

Understanding the immune responses elicited by SARS-CoV-2 infection is critical in terms of protection against reinfection and, thus, for public health policy and vaccine development for COVID-19. In this study, using either live SARS-CoV-2 particles or retroviruses pseudotyped with the SARS-CoV-2 S viral surface protein (Spike), we studied the neutralizing antibody (nAb) response in serum samples from a cohort of 140 SARS-CoV-2 qPCR-confirmed infections, including patients with mild symptoms and also more severe forms, including those that required intensive care. We show that nAb titers correlated strongly with disease severity and with anti-spike IgG levels. Indeed, patients from intensive care units exhibited high nAb titers; conversely, patients with milder disease symptoms had heterogeneous nAb titers, and asymptomatic or exclusive outpatient-care patients had no or low nAbs. We found that nAb activity in SARS-CoV-2-infected patients displayed a relatively rapid decline after recovery compared to individuals infected with other coronaviruses. Moreover, we found an absence of cross-neutralization between endemic coronaviruses and SARS-CoV-2, indicating that previous infection by human coronaviruses may not generate protective nAbs against SARS-CoV-2. Finally, we found that the D614G mutation in the spike protein, which has recently been identified as the current major variant in Europe, does not allow neutralization escape. Altogether, our results contribute to our understanding of the immune correlates of SARS-CoV-2-induced disease, and rapid evaluation of the role of the humoral response in the pathogenesis of SARS-CoV-2 is warranted.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19 Serological Testing , COVID-19/immunology , COVID-19/pathology , SARS-CoV-2/immunology , Severity of Illness Index , Adult , Aged , Aged, 80 and over , Amino Acid Substitution , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/blood , COVID-19/virology , Female , Humans , Kinetics , Longitudinal Studies , Male , Middle Aged , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
12.
J Clin Virol ; 132: 104636, 2020 11.
Article in English | MEDLINE | ID: covidwho-747685

ABSTRACT

BACKGROUND: Facing the emergence of a new RNA virus, clinical laboratories are often helpless in the case of a shortage of reagents recommended by Reference Centres. OBJECTIVES: To compare five open one step RT-qPCR reagents to the SuperScript™ III Platinum™ One-Step qRT-PCR kit (Invitrogen) considered as the reference one in France at the beginning of the pandemic for detection of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in respiratory specimens by using a laboratory-developed assay targeting the viral RNA dependant RNA polymerase (RdRp) gene. STUDY DESIGN: A total of 51 NUCLISENS easyMAG extracts from respiratory specimens was tested on ABI 7500 thermocycler with TaqMan Fast Virus 1-Step Master Mix (Applied Biosystems), Luna® Universal Probe One-Step RT-qPCR Kit (New England Biolabs), GoTaq® Probe 1- Step RT-qPCR System (Promega), LightCycler® Multiplex RNA Virus Master (Roche) and One-step PrimeScript RT-PCR kit (Takara). The CT values obtained using the 5 challenged reagents were compared to those obtained using the reference assay. RESULTS: The percentages of concordance were all above 95 %. When comparing the CT values of the 48 extracts exhibiting CT values < 35 obtained with the reference reagent, the results were similar between the reagents although the differences of CT values were quite dispersed. CONCLUSIONS: All five reagents can be considered as alternative reagents to the reference for detecting SARS-CoV-2 RNA.


Subject(s)
COVID-19/diagnosis , RNA, Viral/analysis , Real-Time Polymerase Chain Reaction/methods , Real-Time Polymerase Chain Reaction/standards , SARS-CoV-2/genetics , Humans , Nasopharynx/virology , Sensitivity and Specificity , Sputum/virology , Trachea/virology
SELECTION OF CITATIONS
SEARCH DETAIL