Ultraviolet Dosage and Decontamination Efficacy was Widely Variable across 14 UV Devices after Testing a Dried Enveloped Ribonucleic Acid Virus Surrogate for SARS-CoV-2

  1. Tony L. Buhr
  2. Erica Borgers-Klonkowski
  3. Bradford W. Gutting
  4. Emlyn E. Hammer
  5. Shelia M. Hamilton
  6. Brett M. Huhman
  7. Stuart L. Jackson
  8. Neil L. Kennihan
  9. Samuel D. Lilly
  10. John D. Little
  11. Brooke B. Luck
  12. Emily A. Matuczinski
  13. Charles T. Miller
  14. Rachel E. Sides
  15. Vanessa L. Yates
  16. Alice A. Young

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Abstract

Aims

The dosages and efficacy of 14 ultraviolet (UV) decontamination technologies were measured against a SARS-CoV-2 surrogate virus that was dried on to different materials for lab and field testing.

Methods and Results

A live enveloped, ribonucleic acid (RNA) virus surrogate for SARS- CoV-2 was dried on stainless steel 304 (SS304), Navy Top Coat-painted SS304 (NTC), cardboard, polyurethane, polymethyl methacrylate (PMMA), and acrylonitrile butadiene styrene (ABS) at > 8.0 log 10 plaque-forming units (PFU) per test coupon. The coupons were then exposed to UV radiation during both lab and field testing. Commercial and prototype UV- emitting devices were measured for efficacy: 4 handheld devices, 3 room/surface-disinfecting machines, 5 air-disinfection devices, and 2 larger custom-made machines. UV device dosages ranged from 0.01-729 mJ cm -2 . Anti-viral efficacy among the different UV devices ranged from no decontamination up to nearly achieving sterilization. Importantly, cardboard required far more dosage than SS304.

Conclusions

Enormous variability in dosage and efficacy was measured among the different UV devices. Porous materials limit the utility of UV decontamination.

Significance and Impact of the Study

UV devices have wide variability in dosages, efficacy, hazards, and UV output over time indicating that each UV device needs independent technical measurement and assessment for product development, prior to, and during use.

Article activity feed

  1. Version published to 10.1101/2022.01.27.478063v2 on bioRxiv
  2. ScreenIT

    SciScore for 10.1101/2022.01.27.478063: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Ethicsnot detected.
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    The data acquisition software used National Instruments LabVIEW for all aspects except direct control of the translation stages.
    LabVIEW
    suggested: (LabView , RRID:SCR_014325)
    Post-processing was accomplished with the Jupyter software environment, with discrete Python code blocks to allow for processing of specific sources as needed.
    Python
    suggested: (IPython, RRID:SCR_001658)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    These limitations of UV light are well documented by regulatory agencies and those limitations also apply to SARS-CoV-2 (Anonymous 2021a and 2021b). Nonetheless, UV efficacy was measurable and very high dosages were effective even on relatively porous materials like cardboard. It is unlikely that UV would be useful for highly porous fabrics used to make bags, carpeting and clothing, and those were not tested. In contrast, hot, humid air inactivates dirty microbes with similar kinetics regardless of material porosity (e.g. Buhr et al 2012, 2015, 2016, 2020). This is a hallmark difference between highly penetrative decontaminants and a surface decontaminant like UV. The prototype medium conveyer generated the highest virus inactivation per dosage. Inoculated coupons were exposed to UV-C light on three sides since the coupons were set on a flat surface during exposure in the conveyer. The big UV box also generated high levels of virus inactivation, but the medium conveyer was highest efficacy dose-1. In contrast the handheld devices, pulsed Xenon devices, LEM, and the original prototypes A, B, and C, and modified prototype B were all evaluated with a UV source emitted from predominantly one direction with slightly varying angles of exposure. The increased angles of exposure in the conveyer and big box likely improved UV-C penetration. Hence, the unique geometry, design and electronics of each device impacted the effectiveness above and beyond the wavelength and dosage. Anti-vira...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

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  3. Version published to 10.1101/2022.01.27.478063v1 on bioRxiv