A safer UV light has been discovered as an effective way of killing the virus causing Covid-19 in a study recently conducted by researchers at Hiroshima University. An ultraviolet light having a wavelength of 222 nanometers and safe around humans can kill the Coronavirus.
This is the first-ever research that has proved its potency against Coronavirus. Other studies that involve 222 nm UVC have only evaluated its efficacy in getting rid of seasonal coronaviruses that have a similar structure to the SARS-CoV-2 but not on the COVID-19-causing virus itself. A nanometer is the same as a billionth of a meter.
A vitro experiment by researchers at Hiroshima University revealed that 99.7% of the SARS-CoV-2 viral culture was eliminated after exposing it to 222 nm UVC irradiation at 0.1 mW/cm2 for 30 seconds. The study is published in the American Journal of Infection Control.
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Ushio’s Care222TM krypton-chloride excimer lamp was used to conduct tests. A 100 microliter solution that contained the virus (ca. 5 × 106 TCID50/mL) was spread onto a 9-centimeter sterile polystyrene plate. The plates were allowed to get dry in a bio-safety cabinet at room temperature before the Far-UVC lamp 24 centimetres was placed above the plates’ surface
An ultraviolet light featuring a wavelength of 222 nm cannot penetrate the outer layer of the human eye and skin, making it harmless to the living cells beneath. Therefore, it is a safer alternative but equally effective to the more damaging 254 nm UVC germicidal lamps used to disinfect healthcare facilities.
254 nm UVC can only be used in sanitizing empty rooms since it is harmful to exposed human tissues. However, 222 nm UVC can also be used as a disinfection system for occupied public spaces like hospitals where nosocomial infections are a possibility.
Researchers suggest that the effectiveness and safety of 222 nanometer UVC in eliminating SARS-CoV-2 viruses in surfaces be further evaluated.
The Hiroshima University scientists have conducted four COVID-19 studies and one of them is the far-UVC research. The research is funded by the Japan Agency for Medical Research and Development.