Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 7 de 7
Filter
1.
Clinical Cancer Research ; 27(6 SUPPL 1), 2021.
Article in English | EMBASE | ID: covidwho-1816891

ABSTRACT

Background: Serology tests for detecting the antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can identify previous infection and help to confirm the presence of current infection. Objective: The aim of this study was to evaluate the performances of a newly developed high throughput immunoassay for anti-SARS-CoV-2 IgG antibody detection. Results: Clinical agreement studies were performed in 77 COVID-19 patient serum samples and 226 negative donor serum/plasma samples. Positive percent agreement (PPA) was 46.15% (95% CI: 19.22% ∼74.87%), 61.54% (95% CI: 31.58% ∼86.14%), and 97.53% (95% CI: 91.36% ∼99.70%) for samples collected on 0-7 days, 8-14 days, and ≥15 days from symptom onset, respectively. Negative Percent Agreement (NPA) was 98.23% (95% CI: 95.53% ∼99.52%). No cross-reactivity was observed to patient samples positive for IgG antibodies against the following pathogens: HIV, HAV, HBV, RSV, CMV, EBV, Rubella, Influenza A, and Influenza B. Hemoglobin (200 mg/dL), bilirubin (2 mg/dL) and EDTA (10 mM) showed no significant interfering effect on this assay. Conclusion: An anti-SARS-CoV-2 IgG antibody assay with high sensitivity and specificity has been developed. With the high throughput, this assay will speed up the anti-SARS-CoV-2 IgG testing.

2.
Clinical Cancer Research ; 27(6 SUPPL 1), 2021.
Article in English | EMBASE | ID: covidwho-1816890

ABSTRACT

Objectives Sensitive and high throughput molecular testing availability is essential during the COVID-19 pandemic. The vast majority of the SARS-CoV-2 molecular assays use nasopharyngeal or oropharyngeal swab specimens collected from suspected individuals. However, collecting these specimens has apparent drawbacks, including discomfort to patients and exposure risk to healthcare workers. Methods We developed and validated of QuantiVirus™ SARS-CoV-2 multiplex test using saliva as the testing specimens with pooling. Results The analytical sensitivity (LOD) was confirmed to be 100-200 copies/mL. For clinical evaluation, 85 known positive and 90 knowns negative NPS specimens were showed a positive predictive agreement of 100% and a negative predictive agreement of 98.9%. Twenty paired NPS and saliva samples were tested and showed overall 80% concordance rate without significant difference between NPS and saliva specimens by Wilcoxon signed-rank test (p=0.13). On a large scale of saliva-based population screening, the positive test rate was 1.79% among 389 saliva specimens. Furthermore, saliva sample pooling up to 6 samples for SARS-CoV-2 detection is feasible with sensitivity of 94.8% and specificity of 100%. Conclusions These results demonstrated that the clinical performance of saliva-based testing is comparable to that of NPS-based testing, and that pooling of saliva specimens for SARS-CoV-2 detection is feasible.

3.
PubMed; 2021.
Preprint in English | PubMed | ID: ppcovidwho-333666

ABSTRACT

The exact mechanism of coronavirus replication and transcription is not fully understood;however, a hallmark of coronavirus transcription is the generation of negative-sense RNA intermediates that serve as the templates for the synthesis of positive-sense genomic RNA (gRNA) and an array of subgenomic mRNAs (sgRNAs) encompassing sequences arising from discontinuous transcription. Existing PCR-based diagnostic assays for SAR-CoV-2 are qualitative or semi-quantitative and do not provide the resolution needed to assess the complex transcription dynamics of SARS-CoV-2 over the course of infection. We developed and validated a novel panel of specially designed SARS-CoV-2 ddPCR-based assays to map the viral transcription profile. Application of these assays to clinically relevant samples will enhance our understanding of SARS-CoV-2 replication and transcription and may also inform the development of improved diagnostic tools and therapeutics. HIGHLIGHTS: We developed a novel panel of 7 quantitative RT-ddPCRs assays for SARS-Cov-2Our panel targets nongenic and genic regions in genomic and subgenomic RNAsAll assays detect 1-10 copies and are linear over 3-4 orders of magnitudeAll assays correlated with the clinical Abbott SARS-CoV-2 Viral Load AssayClinical samples showed higher copy numbers for targets at the 3' end of the genome.

4.
PubMed; 2020.
Preprint in English | PubMed | ID: ppcovidwho-296875

ABSTRACT

We report very low SARS-CoV-2 seroprevalence in two San Francisco Bay Area populations. Seropositivity was 0.26% in 387 hospitalized patients admitted for non-respiratory indications and 0.1% in 1,000 blood donors. We additionally describe the longitudinal dynamics of immunoglobulin-G, immunoglobulin-M, and in vitro neutralizing antibody titers in COVID-19 patients. Neutralizing antibodies rise in tandem with immunoglobulin levels following symptom onset, exhibiting median time to seroconversion within one day of each other, and there is >93% positive percent agreement between detection of immunoglobulin-G and neutralizing titers.

5.
PLoS ONE ; 16(2), 2021.
Article in English | CAB Abstracts | ID: covidwho-1410710

ABSTRACT

Background: Sensitive and high throughput molecular detection assays are essential during the coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The vast majority of the SARS-CoV-2 molecular assays use nasopharyngeal swab (NPS) or oropharyngeal swab (OPS) specimens collected from suspected individuals. However, using NPS or OPS as specimens has apparent drawbacks, e.g. the collection procedures for NPS or OPS specimens can be uncomfortable to some people and may cause sneezing and coughing which in turn generate droplets and/or aerosol particles that are of risk to healthcare workers, requiring heavy use of personal protective equipment. There have been recent studies indicating that self-collected saliva specimens can be used for molecular detection of SARS-CoV-2 and provides more comfort and ease of use for the patients. Here we report the performance of QuantiVirusTM SARS-CoV-2 test using saliva as the testing specimens with or without pooling. Methods Development and validation studies were conducted following FDA-EUA and molecular assay validation guidelines. Using SeraCare Accuplex SARS-CoV-2 reference panel, the limit of detection (LOD) and clinical performance studies were performed with the QuantiVirusTM SARS-CoV-2 test. For clinical evaluation, 85 known positive and 90 known negative clinical NPS samples were tested. Additionally, twenty paired NPS and saliva samples collected from recovering COVID-19 patients were tested and the results were further compared to that of the Abbott m2000 SARS-CoV-2 PCR assay. Results of community collected 389 saliva samples for COVID-19 screening by QuantiVirusTM SARS-CoV-2 test were also obtained and analyzed. Additionally, testing of pooled saliva samples was evaluated.

6.
Topics in Antiviral Medicine ; 29(1):62, 2021.
Article in English | EMBASE | ID: covidwho-1250779

ABSTRACT

Background: SARS-CoV-2 is transcribed as genomic RNA (gRNA) and different subgenomic RNAs (sgRNA), allowing variation in viral gene expression. However, the extent and clinical significance of subgenomic transcription remain unknown. We hypothesized that SARS-CoV-2 RNA levels would vary between genome regions and between patients, tissues, and sample types (cells or fluids). Methods: We designed and validated 7 novel RT-ddPCR assays that target the 5' and 3' untranslated regions (UTR), non-structural genes found only in full length gRNA [Main Proteinase (NSP5) and RNA dependent RNA polymerase (RdRp)], and 3' structural genes [Spike (S), membrane (M), and nucleocapsid (N)] that are also contained in different sgRNAs. Assay efficiencies were measured on standards derived from plasmids and viral stock supernatants. Levels of all 7 RNA regions were measured in nucleic acid extracted by the Abbott m2000 platform from nasopharyngeal (NP) swabs from 3 SARS-CoV-2 infected individuals, and in cells and supernatant from NP, oropharynx (OP), and saliva isolated from 3 additional individuals. Results: In all samples, levels of 3' targets (M, N, and 3'UTR) tended to be higher than 5' targets (5' UTR, NSP5, and RdRp), suggesting an excess of 3' sgRNAs (3'UTR/5'UTR=2.4-6.2 and nucleocapsid/RdRp=1.1-7.5 for NP samples;n=6, p=0.03). All SARS-CoV-2 RNAs were detected in both cells and supernatant from NP, OP, and saliva, but tended to be higher in the NP than OP. In saliva but not NP or OP, levels of gRNA/μL sample were consistently higher in the cells compared to supernatant (cell/sup=2.7-44.8). Surprisingly, the excess of 3' over 5' viral RNAs was even greater in the supernatant (3'UTR/5'UTR=8.2-38.7) compared to cells (3'UTR/5'UTR=1.5-6.2) from NP, OP, and saliva (p=0.016 across all), suggesting a greater excess of sgRNAs in the cell-free fluids. Conclusion: The higher levels of 3' targets suggest an excess of sgRNA in all samples. Assays that target 3' regions found in sgRNAs (N, 3'UTR) may be more sensitive for detecting SARS-CoV-2, but may not indicate infectious virus. The greater excess of 3' transcripts in cell-free fluids suggests that sgRNAs are released from cells and/or persist to a greater degree than gRNAs. Future studies should investigate how levels of sgRNA change over the course of infection in cells and cell-free fluids, and whether sgRNA levels correlate with measures of disease transmission or severity.

7.
Mathematics ; 9(8), 2021.
Article in English | Scopus | ID: covidwho-1208674

ABSTRACT

With the effects of the COVID-19 pandemic, the e-commerce trend is driving faster, significantly impacting supply chains around the world. Thus, the importance of logistics and supply chain functions has been amplified in almost every business that ships physical goods. In Vietnam, the logistics service sector has seen rapid expansion. Since more and more businesses are seeking third-party logistics (3PL) providers to outsource the logistics functions, this article aims to offer decision-makers an integrated and consistent model for evaluating and selecting the most efficient 3PLs. To this end, the authors exploit a hybrid multi-criteria method which is fuzzy analytic hierarchy process (FAHP) and fuzzy vlsekriterijumska optimizacija i kompromisno resenje (FVIKOR) while examining the most influential and conflicting criteria regarding economic, service level, environmental, social, and risk aspects. Fuzzy information in the natural decision-making process is considered, linguistic variables are used to mitigate the uncertain levels in the criteria weights. First, FAHP (the weighting method) is adopted to evaluate and calculate each criterion’s relative significant fuzzy weight. FVIKOR (the compromised ranking method) is then used to rank the alternatives. The combination of FAHP and FVIKOR methods provides more accurate ranking results. As a result, reliability and delivery time, voice of customer, logistics cost, network management, and quality of service are the most impactful factors to the logistics outsourcing problem. Eventually, the optimized 3PLs were determined that fully meet the criteria of sustainable development. The developed integrated model offers the complete and robust 3PLs evaluation and selection process and can also be a powerful decision support tool for other industries. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

SELECTION OF CITATIONS
SEARCH DETAIL