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. 2021 Dec 3;11(1):23379.
doi: 10.1038/s41598-021-02942-4.

Virucidal efficacy of guanidine-free inactivants and rapid test buffers against SARS-CoV-2

Katherine Davies  1 , Ulrike Arnold  1 , Hubert Buczkowski  1 , Christopher Burton  1 , Stephen R Welch  1 , Nicole Green  1 , Rhea Strachan  1 , Tracy Beetar-King  1 , Peter Spencer  1 , Nipunadi Hettiarachchi  1 , Matthew J Hannah  1 , Matthew Jones  1 , Patricia A Cane  1 , Christine B Bruce  1 , Neil Woodford  2 , Allen D G Roberts  1 , Marian J Killip  3
Affiliations

Virucidal efficacy of guanidine-free inactivants and rapid test buffers against SARS-CoV-2

Katherine Davies et al. Sci Rep. .

Abstract

A pathogen inactivation step during collection or processing of clinical samples has the potential to reduce infectious risks associated with diagnostic procedures. It is essential that these inactivation methods are demonstrated to be effective, particularly for non-traditional inactivation reagents or for commercial products where the chemical composition is undisclosed. This study assessed inactivation effectiveness of twenty-four next-generation (guanidine-free) nucleic acid extraction lysis buffers and twelve rapid antigen test buffers against SARS-CoV-2, the causative agent of COVID-19. These data have significant safety implications for SARS-CoV-2 diagnostic testing and support the design and evidence-based risk assessment of these procedures.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Inactivation testing workflow. SARS-CoV-2 suspensions are treated with guanidine-free molecular extraction reagents or LFIA buffers and mixed before incubating for the recommended contact time. If filtration is required to remove product-associated cytotoxicity, samples are added to a purification resin and centrifuged to elute and immediately titrated. If filtration steps are not required, samples are immediately titrated. Image created in Inkscape version 1.0 https://inkscape.org.
Figure 2
Figure 2
SARS-CoV-2 titre reductions following treatment with guanidine-free molecular extraction reagents and LFIA buffers. SARS-CoV-2 suspension was treated with guanidine-free molecular extraction reagents (a) or LFIA buffers (b), using the contact times and concentrations stated in Tables 1 and 2, respectively. SARS-CoV-2 was mock-treated with an equivalent volume of PBS in parallel. Samples were purified by methods indicated in Tables 1 and 2 to remove product-associated cytotoxicity, then titrated by TCID50 on Vero E6 cells to determine virus titre. All treatments and mock-treatments were performed in triplicate; bars show the mean of triplicate inactivation tests and error bars the standard deviation. The limit of detection for each test was determined using the cytotoxicity control for each test, and is indicated on the graph for each test by a dashed line. Where cytotoxicity of sample replicates and/or treatment times for a product differed, the highest LOD for the entire test is displayed. Variation in virus titres for PBS-treated samples between product tests was due to differences in the titre of virus stock used, the ratio of sample to product or PBS used for treatment, and differing virus recovery following sample filtration with different methods6. VRCK: Virus RNA Collection Kit; VPS: Virus Preservation System; Triton X-100 red.: Triton X-100 reduced. Graphs created in GraphPad Prism version 9 https://graphpad.com.
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References

    1. Hasell J, et al. A cross-country database of COVID-19 testing. Sci. Data. 2020;7:345. doi: 10.1038/s41597-020-00688-8. - DOI - PMC - PubMed
    1. Public Health England. COVID-19: Safe Handling and Processing for Laboratories. https://www.gov.uk/government/publications/wuhan-novel-coronavirus-guida... (2020).
    1. World Health Organization. Laboratory BIOSAFETY Guidance Related to Coronavirus Disease (COVID-19)https://www.who.int/publications/i/item/laboratory-biosafety-guidance-re...) (2020).
    1. Centers for Disease Control and Prevention. Guidance for SARS-CoV-2 Point-of-Care Testing. https://www.cdc.gov/coronavirus/2019-ncov/lab/point-of-care-testing.html (2020). - PubMed
    1. Farrell, R. E. RNA Isolation Strategies. Rna Methodologies: Laboratory Guide for Isolation and Characterization, 5th Edition, 75–115. 10.1016/B978-0-12-804678-4.00003-8 (2017).

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