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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.
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.

4.
2020 Ieee International Conference on Bioinformatics and Biomedicine ; : 2320-2327, 2020.
Article in English | Web of Science | ID: covidwho-1354392

ABSTRACT

With the recent outbreak of coronavirus disease 2019 (COVID-19), human life and the world economy have been severely affected, the propagation and scale of COVID-19 is top of mind for everyone. To reconstruct the development trend of COVID-19, we investigate the issue of the epidemic spreading process under vigorous non-pharmaceutical interventions. Here, an improved Susceptible-Exposed-Infectious-Recovered (SEIR) model with dynamic variables (i.e., health exposure individuals and close contacts) is proposed to predict the scale of COVID-19 and its dynamic evolution. We assume that the number of contacts and the reproduction number of COVID-19 changes dynamically over time. Then a gradient descent method is applied to estimate the effective reproduction number. We use the proposed model to reconstruct the dynamic transmission of COVID-19 in Chongqing between 14 January and 24 March 2020. The results show a similar development trend with a real-world epidemic. Our work has important implications when considering strategies for continuing surveillance and interventions to eventually contain outbreaks of COVID-19.

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