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A new study has revealed that low doses of ultraviolet C (far-UVC) light can kill airborne flu viruses without harming human tissues. The development comes as the UK is hit by its worst flu outbreak since 2011. The US Centers for Disease Control and Prevention (CDC) said on Friday that this year's flu season in the country is as bad as the 2009 swine flu pandemic that killed around 200,000 people worldwide.

The new study conducted at the Center for Radiological Research at Columbia University Irving Medical Center (CUIMC) suggest that the use of overhead far-UVC light in public places such as hospitals, offices, schools, airports, airplanes, etc could control the seasonal influenza epidemics, as well as influenza pandemics.

Scientists have known for decades that broad-spectrum UVC light (wavelength of between 200 to 400 nanometers, or nm) is highly effective in killing viruses and bacteria, but "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 at the Vagelos College of Physicians and Surgeons and director of the Center for Radiological Research at Columbia.

Five years ago, Brenner and his colleagues hypothesized that a narrow spectrum of ultraviolet light called far-UVC could kill microbes without damaging healthy tissue. "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," said Brenner.

Now, they have shown that UVC light can actually effectively kill airborne influenza without harming human skin. In the new study, aerosolized particles of the H1N1 seasonal flu virus were released into a test chamber and were exposed to very low doses of far-UVC light. A control group of the aerosolized virus was released into a test chamber that was not exposed to the UVC light.

They found that far-UVC light efficiently rendered the flu viruses inactive, while a control group of bacteria remained active. Brenner and his team are working with a company to develop a lamp version of it to make it commercially available.

"The lamp we're using at the moment costs less than $1,000, and you can imagine that if it were put into general circulation, the price would drop dramatically," he says. "We don't see cost as being a limiting factor here."