Ultraviolet C light with a wavelength of 222nm effectively kills SARS-CoV-2 and is safe to use around humans, claim researchers in Japan.
The findings from a team at Hiroshima University are said to be the first that prove the efficacy of 222nm UVC light against the virus that causes COVID-19.
According to Hiroshima University, other studies involving 222nm UVC (Far-UVC) have only looked at its potency in eradicating seasonal coronaviruses that are structurally similar to the SARS-CoV-2 but not on the COVID-19-causing virus itself.
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An in vitro experiment by HU researchers showed that 99.7 per cent of the SARS-CoV-2 viral culture was killed after a 30-second exposure to 222nm UVC irradiation at 0.1mW/cm2. The study is published in the American Journal of Infection Control.
Tests were conducted using an Ushio Care222 krypton-chloride excimer lamp. A 100µl solution containing the virus (ca. 5 × 106 TCID50/mL) was spread onto a 9cm sterile polystyrene plate. The researchers allowed it to dry in a biosafety cabinet at room temperature before placing the Far-UVC lamp 24cm above the surface of the plates.
A wavelength of 222nm UVC cannot penetrate the outer, non-living layer of the human eye and skin and will not harm the living cells beneath. This makes it a safer but equally potent alternative to the more damaging 254nm UVC germicidal lamps being used increasingly to disinfect healthcare facilities.
Since 254nm UVC harms exposed human tissues, it can only be used to sanitise empty rooms. But 222nm UVC can be a promising disinfection system for occupied public spaces including hospitals where nosocomial infections are possible.
The researchers, however, suggest further evaluation of the safety and effectiveness of 222nm UVC irradiation in killing SARS-CoV-2 viruses in real-world surfaces.
Come on scientists, test it, prove it, make it and let’s use it.
Shine a bright light on it. Where have I heard this before?
David. Check out a company, Ultratek. I think they have this
Hi
I checked the International UV Association. They will not support FAR UV because it is not tested on people or its effects upon make-up for example. There has been a lot with shaven mice but that is no good. The only firm with tests and certificates and approved by UK government, FDA and CE marked etc etc are http://www.pplpro.co.uk
The IUVA position:
https://www.iuva.org/Projects-Articles-Repository/8926263
“The case for far UV-C light (200 – 225 nm) is less certain. While evidence in the laboratory suggests that it may be safe under some conditions, based primarily on animal studies and not on longitudinal human studies, there is a lack of protocols to govern the safe construction and operation of such devices.”