UV light for disinfection_UV BARx1_EFSEN

The effect of EFSENs UV BARx1 proven by new research establishing the UVC dose required for disinfection of SARS CoV-2 (the Covid-19 virus)

New research from two independent studies provides data for inactivation of SARS CoV-2 (the Covid-19 virus) with UVC light at 254 nm. Following the latest scientific advances, EFSEN updates the recommendations for use of UV BARx1 and UV BARx1 PRO, with new, more beneficial values replacing the previous estimated averages based on old studies. 

Italian scientists, when evaluating the virucidal effects of UVC irradiation, came to the conclusion that 3,7 mJ/cm2 provides a log3 reduction, that is 99.9% disinfection, of SARS CoV-2 (Covid-19 virus). Their study show that this is enough to successfully inactivate the viruses in saliva remaining after a an infected person coughing, so that no spread can occur. The disinfection effect is evaluated by an in vitro SARS-CoV-2 (Covid-19 virus) infection assay, exposing live cells to the virus before and after UVC exposure. The survival of cells exposed to UVC-inactivated virus, and the death of cells exposed to untreated virus, indicates a successful disinfection [1].

Research from Signify and Boston University found 5 mJ/cm2 (for a log2 reduction) [2], which would correspond to 7,5 mJ/cm2 (for a log3 reduction). 

Both those studies shows significantly reduced dose requirements compared to the previous estimate (20,1 mJ/cm2 for a log3 reduction)[3] which was based on an average for different related viruses in the coronaviridae family.

In light of this new pre-publications, we at EFSEN have decided to adjust our dose recommendation for disinfecting SARS CoV-2 (Covid-19 virus). While the works presented indicates 3,7-7,5 mJ/cm2 for a log3 reduction, we have chosen to add a margin to this when updating our recommendations. Taking this into account, our new recommendations are 10 mJ/cm2 for a log3 reduction, down from 20 mJ/cm2. This corresponds to just over one second exposure (or 7,5m/min) at 10 cm with UV BARx1 and approximately half a second (or 11,5m/min) with UV BARx1 PRO.

Stay tuned for EFSENs upcoming article with more information regarding this!

[1] A. Bianco et al., “UV-C irradiation is highly effective in inactivating and inhibiting SARS-CoV-2 replication.” Cold Spring Harbor Laboratory, 07-Jun-2020.
[2] https://www.signify.com/global/our-company/news/press-releases/2020/20200616-signify-boston-university-validate-effectiveness-signify-uvc-light-sources-on-inactivating-virus-that-causes-covid19?linkId=90981328 , cited 2020-06-17.
[3] Wladyslaw J. Kowalski, T. J. Walsh, and V. Petraitis, “2020 COVID-19 Coronavirus Ultraviolet Susceptibility,” Unpublished, 2020.

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