December 18, 2020 | New five plex RT-qPCR test, novel amplification-free rapid SARS-CoV-2 nucleic acid detection platform, and why temperature screening doesn’t work to diagnose or control COVID-19 spread. Plus: new SARS-CoV-2 antigen ELISA.
Editor’s Note: The COVID-19 research roundups will be taking off for the upcoming holidays. We’ll return in January.
Research Updates
British researchers have developed two versions of a unique five plex RT-qPCR test, termed CoV2-ID, that allows the detection of three viral target genes, a human internal control for confirming the presence of human cells in a sample and a control artificial RNA for quality assessment and potential quantification. In their publication in Scientific Reports, they propose using multiple cycle fluorescence detection, rather than real-time PCR to reduce significantly the time taken to complete the assay as well as assuage the misunderstandings underlying the use of quantification cycles. They also developed an assay to identify mutant genotypes, noting that all of the samples locally gathered have a mutant genotype while a sample originating elsewhere has the wild type. DOI: 10.1038/s41598-020-79233-x
In an editorial in Open Forum Infectious Diseases, researchers at Johns Hopkins Medicine and the University of Maryland School of Medicine describes why temperature screening—primarily done with a non-contact infrared thermometer (NCIT)—doesn't work as an effective strategy for stemming the spread of COVID-19. Readings obtained with NCITs are influenced by numerous human, environmental and equipment variables, all of which can affect their accuracy, reproducibility and relationship with the measure closest to what could be called the 'body temperature', they write. DOI: 10.1093/ofid/ofaa603
Scientists from the Suzhou Institute of Biomedical Engineering and Technology in China have developed a novel amplification-free rapid SARS-CoV-2 nucleic acid detection platform based on hybrid capture fluorescence immunoassay (HC-FIA). The use of the monoclonal antibody S9.6 is the distinctive feature of this process, which recognizes DNA-RNA double-stranded hybrids and enables the conversion of nucleic acid testing into immunofluorescence on a simple lateral flow dipstick. The whole test procedure involves two steps, namely hybridization and immunofluorescence analysis, and it can be finished in less than an hour. The work was published in Nature Biomedical Engineering. DOI: 10.1038/s41551-020-00655-z
Collaborators from the University of Vermont and Cedars-Sinai describes the performance of Biocogniv's new AI-COVID software. The team found high accuracy in predicting the probability of COVID-19 infection using routine blood tests, which can help hospitals reduce the number of patients referred for scarce PCR testing. Model training used 2183 PCR-confirmed cases from 43 hospitals during the pandemic; negative controls were 10,000 pre-pandemic patients from the same hospitals. External validation used 23 hospitals with 1020 PCR-confirmed cases and 171,734 pre-pandemic negative controls. The main outcome was COVID 19 status predicted using same-day routine laboratory results. Model performance was assessed with area under the receiver operating characteristic (AUROC) curve as well as sensitivity, specificity, and negative predictive value (NPV). Full details are published in the Journal of Medical Internet Research. DOI: 10.2196/24048
Industry Updates
EUROIMMUN has announced the launch of the CE marked SARS-CoV-2 Antigen ELISA for specific determination of the SARS-CoV-2 protein. The assay adds to the Company’s broad product portfolio for COVID-19 diagnostics and supports the molecular PCR tests to aid in diagnosing acute SARS-CoV-2 infections. The Antigen ELISA is a laboratory test able to be applied in semi quantitative automatable detection of the SARS-CoV-2 nucleocapsid protein on a large scale. It is validated for swab sample material from the upper respiratory tract and is useful for testing individuals with acute symptoms that point to COVID-19 or who have had suspected contact with SARS-CoV-2. Validation data revealed 93.6% positive agreement (sensitivity) and 100% negative agreement (specificity) between results obtained with the Antigen ELISA and those obtained with a real time PCR test for detecting the virus. Based on the well-known ELISA technology, the SARS-CoV-2 Antigen assay can be performed in most diagnostic laboratory settings and automatically processed on all open ELISA platforms. Press release.
Sherlock Biosciences has received a $5 million grant from the Bill & Melinda Gates Foundation to continue to advance INSPECTR, its instrument-free, synthetic biology-based molecular diagnostics platform. INSPECTR, which stands for Internal Splint-Pairing Expression Cassette Translation Reaction, uses synthetic biology to enable the creation of instrument-free diagnostic tests that can be conducted at home, at room temperature. INSPECTR can be adapted to work on a simple paper strip test or to provide an electrochemical readout that can be read with a mobile phone. It can also be adapted for use in laboratory or point-of-care settings. The Gates funding will support the development of an over-the-counter disposable product, similar to an at-home pregnancy test, that can be used to detect SARS-CoV-2. Press release.