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1.
Arch Toxicol ; 96(8): 2329-2339, 2022 08.
Article in English | MEDLINE | ID: covidwho-1930384

ABSTRACT

BriLife®, a vector-based vaccine that utilizes the recombinant vesicular stomatitis virus (VSV) platform to express and present the spike antigen of SARS-CoV-2, is undergoing testing in a phase 2 clinical trial in Israel. A nonclinical repeated-dose (GLP) toxicity study in New Zealand white rabbits was performed to evaluate the potential toxicity, local tolerance, immunogenicity and biodistribution of the vaccine. rVSV-ΔG-SARS-CoV-2-S (or vehicle) was administered intramuscularly to two groups of animals (106, 107 PFU/animal, n = 10/sex/group) on three occasions, at 2-week intervals, followed by a 3-week recovery period. Systemic clinical signs, local reactions, body weight, body temperature, food consumption, ophthalmology, urinalysis, clinical pathology, C-reactive protein, viremia and antibody levels were monitored. Gross pathology was performed, followed by organs/tissues collection for biodistribution and histopathological evaluation. Treatment-related changes were restricted to multifocal minimal myofiber necrosis at the injection sites, and increased lymphocytic cellularity in the iliac and mesenteric lymph nodes and in the spleen. These changes were considered related to the inflammatory reaction elicited, and correlated with a trend for recovery. Detection of rVSV-ΔG-SARS-CoV-2-S vaccine RNA was noted in the regional iliac lymph node in animals assigned to the high-dose group, at both termination time points. A significant increase in binding and neutralizing antibody titers was observed following vaccination at both vaccine doses. In view of the findings, it was concluded that the rVSV-ΔG-SARS-CoV-2-S vaccine is safe. These results supported the initiation of clinical trials.


Subject(s)
COVID-19 Vaccines , COVID-19 , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines/adverse effects , Rabbits , SARS-CoV-2 , Tissue Distribution
2.
Front Physiol ; 13: 853317, 2022.
Article in English | MEDLINE | ID: covidwho-1855416

ABSTRACT

The past decade has witnessed tremendous endeavors to deliver novel preclinical in vitro lung models for pulmonary research endpoints, including foremost with the advent of organ- and lung-on-chips. With growing interest in aerosol transmission and infection of respiratory viruses within a host, most notably the SARS-CoV-2 virus amidst the global COVID-19 pandemic, the importance of crosstalk between the different lung regions (i.e., extra-thoracic, conductive and respiratory), with distinct cellular makeups and physiology, are acknowledged to play an important role in the progression of the disease from the initial onset of infection. In the present Methods article, we designed and fabricated to the best of our knowledge the first multi-compartment human airway-on-chip platform to serve as a preclinical in vitro benchmark underlining regional lung crosstalk for viral infection pathways. Combining microfabrication and 3D printing techniques, our platform mimics key elements of the respiratory system spanning (i) nasal passages that serve as the alleged origin of infections, (ii) the mid-bronchial airway region and (iii) the deep acinar region, distinct with alveolated airways. Crosstalk between the three components was exemplified in various assays. First, viral-load (including SARS-CoV-2) injected into the apical partition of the nasal compartment was detected in distal bronchial and acinar components upon applying physiological airflow across the connected compartment models. Secondly, nebulized viral-like dsRNA, poly I:C aerosols were administered to the nasal apical compartment, transmitted to downstream compartments via respiratory airflows and leading to an elevation in inflammatory cytokine levels secreted by distinct epithelial cells in each respective compartment. Overall, our assays establish an in vitro methodology that supports the hypothesis for viral-laden airflow mediated transmission through the respiratory system cellular landscape. With a keen eye for broader end user applications, we share detailed methodologies for fabricating, assembling, calibrating, and using our multi-compartment platform, including open-source fabrication files. Our platform serves as an early proof-of-concept that can be readily designed and adapted to specific preclinical pulmonary research endpoints.

3.
Int J Infect Dis ; 118: 211-213, 2022 May.
Article in English | MEDLINE | ID: covidwho-1838859

ABSTRACT

SARS-CoV-2 Omicron strain emergence raised concerns that its enhanced infectivity is partly due to altered spread/contamination modalities. We therefore sampled high-contact surfaces and air in close proximity to patients who were verified as infected with the Omicron strain, using identical protocols applied to sample patients positive to the original or Alpha strains. Cumulatively, for all 3 strains, viral RNA was detected in 90 of 168 surfaces and 6 of 49 air samples (mean cycle threshold [Ct]=35.2±2.5). No infective virus was identified. No significant differences in prevalence were found between strains.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , RNA, Viral/genetics , Specimen Handling
4.
Nat Commun ; 13(1): 2237, 2022 04 25.
Article in English | MEDLINE | ID: covidwho-1805612

ABSTRACT

The global spread of SARS-CoV-2 led to major economic and health challenges worldwide. Revealing host genes essential for infection by multiple variants of SARS-CoV-2 can provide insights into the virus pathogenesis, and facilitate the development of novel therapeutics. Here, employing a genome-scale CRISPR screen, we provide a comprehensive data-set of cellular factors that are exploited by wild type SARS-CoV-2 as well as two additional recently emerged variants of concerns (VOCs), Alpha and Beta. We identified several host factors critical for SARS-CoV-2 infection, including various components belonging to the Clathrin-dependent transport pathway, ubiquitination, Heparan sulfate biogenesis and host phosphatidylglycerol biosynthesis. Comparative analysis of the different VOCs revealed the host factors KREMEN2 and SETDB1 as potential unique candidates required only to the Alpha variant. Furthermore, the analysis identified GATA6, a zinc finger transcription factor, as an essential proviral gene for all variants inspected. We show that GATA6 directly regulates ACE2 transcription and accordingly, is critical for SARS-CoV-2 cell entry. Analysis of clinical samples collected from SARS-CoV-2 infected individuals shows elevated levels of GATA6, suggesting a role in COVID-19 pathogenesis. Finally, pharmacological inhibition of GATA6 resulted in down-modulation of ACE2 and inhibition of viral infectivity. Overall, we show GATA6 may represent a target for the development of anti-SARS-CoV-2 therapeutic strategies and reaffirm the value of the CRISPR loss-of-function screens in providing a list of potential new targets for therapeutic interventions.


Subject(s)
Angiotensin-Converting Enzyme 2 , COVID-19 , Angiotensin-Converting Enzyme 2/genetics , COVID-19/genetics , Clustered Regularly Interspaced Short Palindromic Repeats/genetics , GATA6 Transcription Factor/genetics , Humans , Peptidyl-Dipeptidase A/metabolism , Proviruses/genetics , SARS-CoV-2/genetics
5.
Vaccines (Basel) ; 10(4)2022 Apr 14.
Article in English | MEDLINE | ID: covidwho-1792374

ABSTRACT

Longevity of the immune response following viral exposure is an essential aspect of SARS-CoV-2 infection. Mild SARS-CoV-2 infection of K18-hACE2 mice was implemented for evaluating the mounting and longevity of a specific memory immune response. We show that the infection of K18-hACE2 mice induced robust humoral and cellular immunity (systemic and local), which persisted for at least six months. Virus-specific T cells and neutralizing antibody titers decreased over time, yet their levels were sufficient to provide sterile immunity against lethal rechallenge six months post-primary infection. The study substantiates the role of naturally induced immunity against SARS-CoV-2 infection for preventing recurring morbidity.

6.
Frontiers in physiology ; 13, 2022.
Article in English | EuropePMC | ID: covidwho-1762527

ABSTRACT

The past decade has witnessed tremendous endeavors to deliver novel preclinical in vitro lung models for pulmonary research endpoints, including foremost with the advent of organ- and lung-on-chips. With growing interest in aerosol transmission and infection of respiratory viruses within a host, most notably the SARS-CoV-2 virus amidst the global COVID-19 pandemic, the importance of crosstalk between the different lung regions (i.e., extra-thoracic, conductive and respiratory), with distinct cellular makeups and physiology, are acknowledged to play an important role in the progression of the disease from the initial onset of infection. In the present Methods article, we designed and fabricated to the best of our knowledge the first multi-compartment human airway-on-chip platform to serve as a preclinical in vitro benchmark underlining regional lung crosstalk for viral infection pathways. Combining microfabrication and 3D printing techniques, our platform mimics key elements of the respiratory system spanning (i) nasal passages that serve as the alleged origin of infections, (ii) the mid-bronchial airway region and (iii) the deep acinar region, distinct with alveolated airways. Crosstalk between the three components was exemplified in various assays. First, viral-load (including SARS-CoV-2) injected into the apical partition of the nasal compartment was detected in distal bronchial and acinar components upon applying physiological airflow across the connected compartment models. Secondly, nebulized viral-like dsRNA, poly I:C aerosols were administered to the nasal apical compartment, transmitted to downstream compartments via respiratory airflows and leading to an elevation in inflammatory cytokine levels secreted by distinct epithelial cells in each respective compartment. Overall, our assays establish an in vitro methodology that supports the hypothesis for viral-laden airflow mediated transmission through the respiratory system cellular landscape. With a keen eye for broader end user applications, we share detailed methodologies for fabricating, assembling, calibrating, and using our multi-compartment platform, including open-source fabrication files. Our platform serves as an early proof-of-concept that can be readily designed and adapted to specific preclinical pulmonary research endpoints.

7.
Arch Virol ; 167(4): 1041-1049, 2022 Apr.
Article in English | MEDLINE | ID: covidwho-1709039

ABSTRACT

SARS-CoV-2, the etiologic agent of the COVID-19 pandemic, emerged as the cause of a global crisis in 2019. Currently, the main method for identification of SARS-CoV-2 is a reverse transcription (RT)-PCR assay designed to detect viral RNA in oropharyngeal (OP) or nasopharyngeal (NP) samples. While the PCR assay is considered highly specific and sensitive, this method cannot determine the infectivity of the sample, which may assist in evaluation of virus transmissibility from patients and breaking transmission chains. Thus, cell-culture-based approaches such as cytopathic effect (CPE) assays are routinely employed for the identification of infectious viruses in NP/OP samples. Despite their high sensitivity, CPE assays take several days and require additional diagnostic tests in order to verify the identity of the pathogen. We have therefore developed a rapid immunofluorescence assay (IFA) for the specific detection of SARS-CoV-2 in NP/OP samples following cell culture infection. Initially, IFA was carried out on Vero E6 cultures infected with SARS-CoV-2 at defined concentrations, and infection was monitored at different time points. This test was able to yield positive signals in cultures infected with 10 pfu/ml at 12 hours postinfection (PI). Increasing the incubation time to 24 hours reduced the detectable infective dose to 1 pfu/ml. These IFA signals occur before the development of CPE. When compared to the CPE test, IFA has the advantages of specificity, rapid detection, and sensitivity, as demonstrated in this work.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , Fluorescent Antibody Technique , Humans , Nasopharynx , Pandemics , RNA, Viral/genetics , Sensitivity and Specificity
8.
Vaccines (Basel) ; 10(2)2022 Feb 14.
Article in English | MEDLINE | ID: covidwho-1699506

ABSTRACT

The emergence of rapidly spreading variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a major challenge to the ability of vaccines and therapeutic antibodies to provide immunity. These variants contain mutations of specific amino acids that might impede vaccine efficacy. BriLife® (rVSV-ΔG-spike) is a newly developed SARS-CoV-2 vaccine candidate currently in phase II clinical trials. It is based on a replication-competent vesicular stomatitis virus (VSV) platform. The rVSV-ΔG-spike contains several spontaneously acquired spike mutations that correspond to SARS-CoV-2 variants' mutations. We show that human sera from BriLife® vaccinees preserve comparable neutralization titers towards alpha, gamma, and delta variants and show less than a three-fold reduction in the neutralization capacity of beta and omicron compared to the original virus. Taken together, we show that human sera from BriLife® vaccinees overall maintain a neutralizing antibody response against all tested variants. We suggest that BriLife®-acquired mutations may prove advantageous against future SARS-CoV-2 VOCs.

9.
Arch Toxicol ; 96(3): 859-875, 2022 03.
Article in English | MEDLINE | ID: covidwho-1634984

ABSTRACT

rVSV-ΔG-SARS-CoV-2-S is a clinical stage (Phase 2) replication competent recombinant vaccine against SARS-CoV-2. To evaluate the safety profile of the vaccine, a series of non-clinical safety, immunogenicity and efficacy studies were conducted in four animal species, using multiple doses (up to 108 Plaque Forming Units/animal) and dosing regimens. There were no treatment-related mortalities or any noticeable clinical signs in any of the studies. Compared to unvaccinated controls, hematology and biochemistry parameters were unremarkable and no adverse histopathological findings. There was no detectable viral shedding in urine, nor viral RNA detected in whole blood or serum samples seven days post vaccination. The rVSV-ΔG-SARS-CoV-2-S vaccination gave rise to neutralizing antibodies, cellular immune responses, and increased lymphocytic cellularity in the spleen germinal centers and regional lymph nodes. No evidence for neurovirulence was found in C57BL/6 immune competent mice or in highly sensitive type I interferon knock-out mice. Vaccine virus replication and distribution in K18-human Angiotensin-converting enzyme 2-transgenic mice showed a gradual clearance from the vaccination site with no vaccine virus recovered from the lungs. The nonclinical data suggest that the rVSV-ΔG-SARS-CoV-2-S vaccine is safe and immunogenic. These results supported the initiation of clinical trials, currently in Phase 2.


Subject(s)
COVID-19 Vaccines/toxicity , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19 Vaccines/immunology , Cricetinae , Female , Membrane Glycoproteins/genetics , Mesocricetus , Mice , Mice, Inbred C57BL , Rabbits , Swine , Vaccination , Vaccines, Synthetic/toxicity , Viral Envelope Proteins/genetics
10.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-296650

ABSTRACT

In this report, we describe four RT-qPCR assays that enable rapid identification of the newly emerging SARS-COV-2 Omicron (B.1.1.529) variant of concern. The assays target Omicron characteristic mutations in the nsp6 (Orf1a), spike and nucleocapsid genes. We demonstrate that the assays are straightforward to assemble and perform, are amendable for multiplexing, and may be used as a reliable first-line tool to identify B.1.1.529 suspected samples. Importantly, this is a preliminary development report. Further validation and optimization of the assays described herein will be published hereafter.

11.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-293181

ABSTRACT

BriLife® (rVSV- ΔG-spike) is a SARS-CoV-2 vaccine candidate based on vesicular stomatitis virus (VSV) platform. We show that sera from BriLife® vaccinees maintain neutralization capacity against alpha, beta, gamma and delta SARS-CoV-2 variants. BriLife® spontaneously-acquired spike mutations, corresponding with key SARS-CoV-2 variants mutations, may contribute to its efficacy against SARS-CoV-2 variants.

12.
Antibodies (Basel) ; 10(4)2021 Nov 08.
Article in English | MEDLINE | ID: covidwho-1512074

ABSTRACT

The use of passively-administered neutralizing antibodies is a promising approach for the prevention and treatment of SARS-CoV-2 infection. Antibody-mediated protection may involve immune system recruitment through Fc-dependent activation of effector cells and the complement system. However, the role of Fc-mediated functions in the efficacious in-vivo neutralization of SARS-CoV-2 is not yet clear, and it is of high importance to delineate the role this process plays in antibody-mediated protection. Toward this aim, we have chosen two highly potent SARS-CoV-2 neutralizing human monoclonal antibodies, MD65 and BLN1 that target distinct domains of the spike (RBD and NTD, respectively). The Fc of these antibodies was engineered to include the triple mutation N297G/S298G/T299A that eliminates glycosylation and the binding to FcγR and to the complement system activator C1q. As expected, the virus neutralization activity (in-vitro) of the engineered antibodies was retained. To study the role of Fc-mediated functions, the protective activity of these antibodies was tested against lethal SARS-CoV-2 infection of K18-hACE2 transgenic mice, when treatment was initiated either before or two days post-exposure. Antibody treatment with both Fc-variants similarly rescued the mice from death reduced viral load and prevented signs of morbidity. Taken together, this work provides important insight regarding the contribution of Fc-effector functions in MD65 and BLN1 antibody-mediated protection, which should aid in the future design of effective antibody-based therapies.

13.
J Infect Dis ; 224(4): 616-619, 2021 08 16.
Article in English | MEDLINE | ID: covidwho-1358460

ABSTRACT

Emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants may influence the effectiveness of existing laboratory diagnostics. In the current study we determined whether the British (20I/501Y.V1) and South African (20H/501Y.V2) SARS-CoV-2 variants of concern are detected with an in-house S1-based antigen detection assay, analyzing spiked pools of quantitative reverse-transcription polymerase chain reaction-negative nasopharyngeal swab specimens. The assay, combining 4 monoclonal antibodies, allowed sensitive detection of both the wild type and the variants of concern, despite accumulation of several mutations in the variants' S1 region-results suggesting that this combination, targeting distinct epitopes, enables both specificity and the universality.


Subject(s)
COVID-19/diagnosis , COVID-19/virology , SARS-CoV-2/classification , Antibodies, Monoclonal/immunology , Antigens, Viral/immunology , Antigens, Viral/isolation & purification , COVID-19/immunology , Humans , Mutation , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/isolation & purification , Viral Load
14.
Nat Commun ; 12(1): 944, 2021 02 11.
Article in English | MEDLINE | ID: covidwho-1078588

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), exhibits high levels of mortality and morbidity and has dramatic consequences on human life, sociality and global economy. Neutralizing antibodies constitute a highly promising approach for treating and preventing infection by this novel pathogen. In the present study, we characterize and further evaluate the recently identified human monoclonal MD65 antibody for its ability to provide protection against a lethal SARS-CoV-2 infection of K18-hACE2 transgenic mice. Eighty percent of the untreated mice succumbed 6-9 days post-infection, while administration of the MD65 antibody as late as 3 days after exposure rescued all infected animals. In addition, the efficiency of the treatment is supported by prevention of morbidity and ablation of the load of infective virions in the lungs of treated animals. The data demonstrate the therapeutic value of human monoclonal antibodies as a life-saving treatment for severe COVID-19 infection.


Subject(s)
Antibodies, Monoclonal/administration & dosage , Antibodies, Neutralizing/administration & dosage , Antibodies, Viral/administration & dosage , COVID-19/immunology , Animals , Antibodies, Monoclonal/genetics , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/genetics , Antibodies, Neutralizing/immunology , Antibodies, Viral/genetics , Antibodies, Viral/immunology , COVID-19/drug therapy , Chlorocebus aethiops , Female , Immunoglobulin G/administration & dosage , Immunoglobulin G/genetics , Immunoglobulin G/immunology , Lung/pathology , Lung/virology , Male , Mice, Inbred C57BL , Mice, Transgenic , SARS-CoV-2/classification , SARS-CoV-2/physiology , Seroconversion , Vero Cells , Viral Load
15.
Microbiol Resour Announc ; 10(1)2021 Jan 07.
Article in English | MEDLINE | ID: covidwho-1015609

ABSTRACT

We report the genome sequences and the identification of genetic variations in eight clinical samples of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Samples were collected from nasopharyngeal swabs of symptomatic and asymptomatic individuals from five care homes for elderly and infirm persons in Israel. The sequences obtained are valuable, as they carry a newly reported nonsynonymous substitution located within the nucleoprotein open reading frame.

16.
Nat Commun ; 11(1): 6402, 2020 12 16.
Article in English | MEDLINE | ID: covidwho-983658

ABSTRACT

The COVID-19 pandemic caused by SARS-CoV-2 imposes an urgent need for rapid development of an efficient and cost-effective vaccine, suitable for mass immunization. Here, we show the development of a replication competent recombinant VSV-∆G-spike vaccine, in which the glycoprotein of VSV is replaced by the spike protein of SARS-CoV-2. In-vitro characterization of this vaccine indicates the expression and presentation of the spike protein on the viral membrane with antigenic similarity to SARS-CoV-2. A golden Syrian hamster in-vivo model for COVID-19 is implemented. We show that a single-dose vaccination results in a rapid and potent induction of SARS-CoV-2 neutralizing antibodies. Importantly, vaccination protects hamsters against SARS-CoV-2 challenge, as demonstrated by the abrogation of body weight loss, and  alleviation of the extensive tissue damage and viral loads in lungs and nasal turbinates. Taken together, we suggest the recombinant VSV-∆G-spike as a safe, efficacious and protective vaccine against SARS-CoV-2.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/immunology , COVID-19/prevention & control , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccines, Synthetic/immunology , Vesicular stomatitis Indiana virus/immunology , Animals , Antibodies, Viral/immunology , Antigens, Viral/immunology , Body Weight , COVID-19/virology , Cell Line , Cricetinae , Disease Models, Animal , Dose-Response Relationship, Immunologic , Genome, Viral , Lung/pathology , Lung/virology , Mice, Inbred C57BL , Mutation/genetics , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/ultrastructure , Vaccination , Viral Load
17.
Nature ; 589(7840): 125-130, 2021 01.
Article in English | MEDLINE | ID: covidwho-752477

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the ongoing coronavirus disease 2019 (COVID-19) pandemic1. To understand the pathogenicity and antigenic potential of SARS-CoV-2 and to develop therapeutic tools, it is essential to profile the full repertoire of its expressed proteins. The current map of SARS-CoV-2 coding capacity is based on computational predictions and relies on homology with other coronaviruses. As the protein complement varies among coronaviruses, especially in regard to the variety of accessory proteins, it is crucial to characterize the specific range of SARS-CoV-2 proteins in an unbiased and open-ended manner. Here, using a suite of ribosome-profiling techniques2-4, we present a high-resolution map of coding regions in the SARS-CoV-2 genome, which enables us to accurately quantify the expression of canonical viral open reading frames (ORFs) and to identify 23 unannotated viral ORFs. These ORFs include upstream ORFs that are likely to have a regulatory role, several in-frame internal ORFs within existing ORFs, resulting in N-terminally truncated products, as well as internal out-of-frame ORFs, which generate novel polypeptides. We further show that viral mRNAs are not translated more efficiently than host mRNAs; instead, virus translation dominates host translation because of the high levels of viral transcripts. Our work provides a resource that will form the basis of future functional studies.


Subject(s)
Gene Expression Profiling , Genome, Viral/genetics , Open Reading Frames/genetics , Protein Biosynthesis , SARS-CoV-2/genetics , Viral Proteins/biosynthesis , Viral Proteins/genetics , Animals , Cell Line , Humans , Molecular Sequence Annotation , Peptides/genetics , Peptides/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA, Viral/genetics , RNA, Viral/metabolism , Ribosomes/metabolism , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Viral Proteins/metabolism
18.
Clin Microbiol Infect ; 26(12): 1658-1662, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-753742

ABSTRACT

OBJECTIVES: Environmental surfaces have been suggested as likely contributors in the transmission of COVID-19. This study assessed the infectivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contaminating surfaces and objects in two hospital isolation units and a quarantine hotel. METHODS: SARS-CoV-2 virus stability and infectivity on non-porous surfaces was tested under controlled laboratory conditions. Surface and air sampling were conducted at two COVID-19 isolation units and in a quarantine hotel. Viral RNA was detected by RT-PCR and infectivity was assessed by VERO E6 CPE test. RESULTS: In laboratory-controlled conditions, SARS-CoV-2 gradually lost its infectivity completely by day 4 at ambient temperature, and the decay rate of viral viability on surfaces directly correlated with increase in temperature. Viral RNA was detected in 29/55 surface samples (52.7%) and 16/42 surface samples (38%) from the surroundings of symptomatic COVID-19 patients in isolation units of two hospitals and in a quarantine hotel for asymptomatic and very mild COVID-19 patients. None of the surface and air samples from the three sites (0/97) were found to contain infectious titres of SARS-Cov-2 on tissue culture assay. CONCLUSIONS: Despite prolonged viability of SARS-CoV-2 under laboratory-controlled conditions, uncultivable viral contamination of inanimate surfaces might suggest low feasibility for indirect fomite transmission.


Subject(s)
COVID-19/transmission , Fomites/virology , Hospitals, Isolation/statistics & numerical data , Housing/statistics & numerical data , Microbial Viability , SARS-CoV-2/isolation & purification , COVID-19/virology , Humans , RNA, Viral/isolation & purification , Surface Properties , Temperature
19.
Int J Infect Dis ; 99: 352-354, 2020 Oct.
Article in English | MEDLINE | ID: covidwho-703985

ABSTRACT

The genetic identification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is based on viral RNA extraction prior to RT-qPCR assay. However, recent studies have supported the elimination of the extraction step. This study was performed to assess the necessity for the RNA extraction, by comparing the efficacy of RT-qPCR in several direct approaches versus the gold standard RNA extraction, in the detection of SARS-CoV-2 in laboratory samples, as well as in clinical oro-nasopharyngeal SARS-CoV-2 swabs. The findings showed an advantage for the extraction procedure; however a direct no-buffer approach might be an alternative, since it identified more than 60% of positive clinical specimens.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/diagnosis , Pneumonia, Viral/diagnosis , RNA, Viral/isolation & purification , Real-Time Polymerase Chain Reaction/methods , Animals , COVID-19 , Chlorocebus aethiops , Feasibility Studies , Humans , Nasal Cavity/virology , Pandemics , RNA, Viral/genetics , SARS-CoV-2 , Vero Cells
20.
Microbiol Resour Announc ; 9(28)2020 Jul 09.
Article in English | MEDLINE | ID: covidwho-638622

ABSTRACT

We announce the genome sequences of two strains of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) isolated in Israel, one imported by a traveler who returned from Japan and the second strain collected from a patient infected by a traveler returning from Italy. The sequences obtained are valuable as early manifestations for future follow-up of the local spread of the virus in Israel.

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