Far ultraviolet C (far-UVC) light can kill airborne flu viruses without harming human tissues: Study

14 February 2018

Researchers at Columbia University Irving Medical Center have found that far ultraviolet C (far-UVC) light can kill airborne flu viruses without harming human tissues.

The results suggest that the use of overhead far-UVC light in schools, hospitals, doctors' offices, airports, airplanes, and other public spaces could provide a potent checkpoint for seasonal influenza epidemics, as also influenza pandemics and drug-resistant tuberculosis.

According to commentators, it is known since decades that broad-spectrum UVC light, having a wavelength of between 200 to 400 nanometers, or nm), is highly effective at killing bacteria and viruses by destroying the molecular bonds that hold their DNA together.

''Unfortunately, conventional germicidal UV light is also a human health hazard and can lead to skin cancer and cataracts, which prevents its use in public spaces,'' said study leader David J Brenner, PhD, the Higgins Professor of Radiation Biophysics Professor of Environmental Health Sciences and director of the Center for Radiological Research at Columbia University Irving Medical Center (CUIMC).

Dr Brenner and colleagues hypothesised several years ago, that a narrow spectrum of ultraviolet light called far-UVC could kill microbes without damaging healthy tissue, using filtered excimer lamps emitting in the 207 to 222?nm wavelength range.

''Far-UVC light has a very limited range and cannot penetrate through the outer dead-cell layer of human skin or the tear layer in the eye, so it's not a human health hazard. But because viruses and bacteria are much smaller than human cells, far-UVC light can reach their DNA and kill them.''

Conventional germicidal lamps are not safe for humans to be around and with prolonged exposure, they can cause skin cancer and cataracts in the eyes. ''So up until now, they're only really practical when people aren't around,'' said Brenner,time.com reported. ''You can sterilize a hospital room, but not when anyone's inside.''

''We wanted to get all the benefits of UV light in terms of killing microbes, but none of the health hazards,'' says Brenner. Earlier studies, on animals and humans, have shown that exposure to far-UVC light does indeed appear to be safe. ''We haven't seen any biological damage to skin cells or eye cells, whereas with conventional UV light we've always seen lots of biological damage,'' he said.

Previous research has also shown that far-UVC light can kill MRSA bacteria, a common cause of infections after surgery.

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