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(searched for: doi:10.1007/s10096-020-04010-7)
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Caroline Nespolo de David, , , , Ingrid Rodrigues Fernandes, Gabriela Oliveira Zavaglia, Luciane Beatriz Kern, , , , et al.
Published: 1 January 2022
by SciELO
Cadernos de Saúde Pública, Volume 38; https://doi.org/10.1590/0102-311x00069921

Abstract:
Point-of-care serological tests for SARS-CoV-2 have been used for COVID-19 diagnosis. However, their accuracy over time regarding the onset of symptoms is not fully understood. We aimed to assess the accuracy of a point-of-care lateral flow immunoassay (LFI). Subjects, aged over 18 years, presenting clinical symptoms suggestive of acute SARS-CoV-2 infection were tested once by both nasopharyngeal and oropharyngeal RT-PCR and LFI. The accuracy of LFI was assessed in periodic intervals of three days in relation to the onset of symptoms. The optimal cut-off point was defined as the number of days required to achieve the best sensitivity and specificity. This cut-off point was also used to compare LFI accuracy according to participants’ status: outpatient or hospitalized. In total, 959 patients were included, 379 (39.52%) tested positive for SARS-CoV-2 with RT-PCR, and 272 (28.36%) tested positive with LFI. LFI best performance was achieved after 10 days of the onset of symptoms, with sensitivity and specificity of 84.9% (95%CI: 79.8-89.1) and 94.4% (95%CI: 91.0-96.8), respectively. Although the specificity was similar (94.6% vs. 88.9%, p = 0.051), the sensitivity was higher in hospitalized patients than in outpatients (91.7% vs. 82.1%, p = 0.032) after 10 days of the onset of symptoms. Best sensitivity of point-of-care LFI was found 10 days after the onset of symptoms which may limit its use in acute care. Specificity remained high regardless of the number of days since the onset of symptoms.
Junqing Wei, ZhiHan Zhao, Fengting Luo, Kuibo Lan, Ruibing Chen,
Published: 21 December 2021
Abstract:
Recently, the coronavirus disease (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally with major impact on public health. Novel methods that enable fast and efficient detection of the virus and the associated biomarkers, such as SARS-CoV-2 antibodies, may provide alterative opportunities for early diagnosis, disease status monitoring, and the development of vaccines. Here, we report the fabrication of a functionalized MoS2-field effect transistor (FET) for sensitive and quantitative detection of antibodies against SARS-CoV-2 spike protein receptor binding domain (S-RBD) in vaccinated serum specimens. The device was modified by SARS-CoV-2 S-RBD fusion protein on the surface and enabled rapid detection of SARS-CoV-2 antibodies. In addition, an on-chip calibration method was established for quantitative measurement. Furthermore, this method was applied to measure the levels of S-RBD antibodies in serum specimens from vaccinated donors. The devices showed no response to negative control samples from individuals who did not receive vaccination, suggesting the high specificity of this method. This study illustrated the successful fabrication of S-RBD functionalized MoS2-FET with potential clinical applications to facilitate vaccine development and efficacy evaluation.
Paula Navarro-Carrera, Patricia Roces-Álvarez, Juan Carlos Ramos-Ramos, Dolores Montero, Itsaso Losantos, ,
Published: 13 December 2021
Access Microbiology, Volume 3; https://doi.org/10.1099/acmi.0.000279

Abstract:
Objectives. Challenges remain and there are still a sufficient number of cases with epidemiological, clinical features and radiological data suggestive of COVID-19 pneumonia that persist negative in their RT-PCR results. The aim of the study was to define the distinguishing characteristics between patients developing a serological response to SARS-CoV-2 and those who did not. Methods. RT-PCR tests used were TaqPath 2019-nCoV Assay Kit v1 (ORF-1ab, N and S genes) from Thermo Fisher Diagnostics and SARS-COV-2 Kit (N and E genes) from Vircell. Serological response was tested using the rapid SARS-CoV2 IgG/IgM Test Cassette from T and D Diagnostics Canada and CMC Medical Devices and Drugs, S.L, CE. Results. In this cross-sectional study, we included a cohort of 52 patients recruited from 31 March 2020 to 23 April 2020. Patients with positive serology had an older average age (73.29) compared to those who were negative (54.82) (P<0.05). Sat02 in 27 of 34 patients with positive serology were below 94% (P<0.05). There was a frequency of 1.5% negative SARS-CoV-2 RT-PCRs during the study period concurring with 36.7% of positivity. Conclusions. Clinical features and other biomarkers in a context of a positive serology can be considered crucial for diagnosis.
Ana Carolina Serafim Vilela, Camila Alves Costa, Suzane Aparecida Oliveira, , Fabiola Souza Fiaccadori, ,
Published: 25 October 2021
The publisher has not yet granted permission to display this abstract.
Mamdouh Sibai, Daniel Solis, , Bryan A. Stevens, Kenji O. Mfuh, Malaya K. Sahoo, Run Z. Shi, James Zehnder, Scott D. Boyd,
Published: 1 April 2021
Journal of Clinical Virology, Volume 139, pp 104818-104818; https://doi.org/10.1016/j.jcv.2021.104818

The publisher has not yet granted permission to display this abstract.
Shalu Yadav, Mohd. Abubakar Sadique, Pushpesh Ranjan, Neeraj Kumar, Ayushi Singhal, Avanish K. Srivastava,
ACS Applied Bio Materials, Volume 4, pp 2974-2995; https://doi.org/10.1021/acsabm.1c00102

The publisher has not yet granted permission to display this abstract.
, Carmen Gherasim, Kelly O’Shea, David M. Manthei, Jesse Chen, Don Giacherio, , James L. Baldwin, James R. Baker Jr
Published: 16 March 2021
Abstract:
Background As COVID-19 vaccines become available, screening individuals for prior COVID-19 infection and vaccine response in point-of-care (POC) settings has renewed interest. We prospectively screened at-risk individuals for SARS-CoV-2 spike and nucleocapsid protein antibodies in a POC setting to determine if it was a feasible method to identify antibody from prior infection. Methods Three EUA-approved lateral flow antibody assays were performed on POC finger-stick blood and compared with serum and a CLIA nucleocapsid antibody immunoassay. Variables including antibody class, time since PCR, and the assay antigen used were evaluated. Results 512 subjects enrolled, of which 104 had a COVID-19 history and positive PCR. Only three PCR-positive subjects required hospitalization, with one requiring mechanical ventilation. The POC results correlated well with the immunoassay (93–97% sensitivity) and using serum did not improve the sensitivity or specificity. Conclusions Finger-stick, POC COVID-19 antibody testing was highly effective in identifying antibody resulting from prior infections in mildly symptomatic subjects. Using high-complexity serum immunoassays did not improve the screening outcome. Almost all individuals with COVID-19 infection produced detectable antibodies to the virus. POC antibody testing is useful as a screen for prior COVID-19 infection, and should be useful in assessing vaccine response.
Qi Song, Xindi Sun, Ziyi Dai, Yibo Gao, Xiuqing Gong, , ,
Published: 22 February 2021
Lab on a Chip, Volume 21, pp 1634-1660; https://doi.org/10.1039/d0lc01156h

Abstract:
COVID-19 is an acute respiratory disease caused by SARS-CoV-2, which has high transmissibility. People infected with SARS-CoV-2 can develop symptoms including cough, fever, pneumonia and other complications, which in severe cases could lead to death. In addition, a proportion of people infected with SARS-CoV-2 may be asymptomatic. At present, the primary diagnostic method for COVID-19 is reverse transcription-polymerase chain reaction (RT-PCR), which tests patient samples including nasopharyngeal swabs, sputum and other lower respiratory tract secretions. Other detection methods, e.g., isothermal nucleic acid amplification, CRISPR, immunochromatography, enzyme-linked immunosorbent assay (ELISA) and electrochemical sensors are also in use. As the current testing methods are mostly performed at central hospitals and third-party testing centres, the testing systems used mostly employ large, high-throughput, automated equipment. Given the current situation of the epidemic, point-of-care testing (POCT) is advantageous in terms of its ease of use, greater approachability on the user's end, more timely detection, and comparable accuracy and sensitivity, which could reduce the testing load on central hospitals. POCT is thus conducive to daily epidemic control and achieving early detection and treatment. This paper summarises the latest research advances in POCT-based SARS-CoV-2 detection methods, compares three categories of commercially available products, i.e., nucleic acid tests, immunoassays and novel sensors, and proposes the expectations for the development of POCT-based SARS-CoV-2 detection including greater accessibility, higher sensitivity and lower costs.
Arantxa Valdivia, Ignacio Torres, Víctor Latorre, Clara Francés‐Gómez, Josep Ferrer, Lorena Forqué, Rosa Costa, Carlos Solano de la Asunción, Dixie Huntley, , et al.
Published: 25 November 2020
Journal of Medical Virology, Volume 93, pp 2301-2306; https://doi.org/10.1002/jmv.26697

The publisher has not yet granted permission to display this abstract.
Published: 25 September 2020
Abstract:
Purpose: Assessment of commercial SARS-CoV-2 immunoassays for their capacity to provide reliable information on sera neutralizing activity is an emerging need. We evaluated the performance of two commercially-available lateral flow immunochromatographic assays (LFIC) (Wondfo SARS-CoV-2 Antibody test and the INNOVITA 2019-nCoV Ab test) in comparison with a SARS-CoV-2 neutralization pseudotyped assay for COVID-19 diagnosis in hospitalized patients, and investigate whether the intensity of the test band in LFIC associates with neutralizing antibody (NtAb) titers.Patients and Methods: Ninety sera were included from 51 patients with moderate to severe COVID-19. A green fluorescent protein (GFP) reporter-based pseudotyped neutralization assay (vesicular stomatitis virus coated with SARS-CoV-2 spike protein) was used. Test line intensity was scored using a 4-level scale (0 to 3+).Results: Overall sensitivity of LFIC assays was 91.1% for the Wondfo SARS-CoV-2 Antibody test, 72.2% for the INNOVITA 2019-nCoV IgG, 85.6% for the INNOVITA 2019-nCoV IgM and 92.2% for the NtAb assay. Sensitivity increased for all assays in sera collected beyond day 14 after symptoms onset (93.9%, 79.6%,93.9% and 93.9%, respectively). Reactivities equal to or more intense than the positive control line (≥2+) in the Wondfo assay had a negative predictive value of 100% and a positive predictive value of 96.4% for high NtAb50 titers (≥1/160).Conclusions: Our findings support the use of LFIC assays evaluated herein, particularly the Wondfo test, for COVID-19 diagnosis. We also find evidence that these rapid immunoassays can be used to predict high SARS-CoV-2-S NtAb50 titers.
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