A UV lamp could prevent the flu from spreading in public

“We’ve known for a century that UV light is extremely efficient at killing microbes, bacteria, and viruses,” says study leader David Brenner, director of the Center for Radiological Research at Columbia University Irving Medical Center. For that reason, UV devices are often used for sterilization — for medical equipment in hospitals, for example, or drinking water for backcountry campers.

But conventional germ-killing lamps aren’t safe for humans. Exposure can cause skin cancer and cataracts in the eyes. “So up until now, they’re only really practical when people aren’t around,” says Brenner. “You can sterilize a hospital room, but not when anyone’s inside.”

About five years ago, Brenner says, the Columbia team came up with a potential solution. Light on the far end of the UV-C spectrum, known as far-UVC, has very short wavelengths. The researchers suspected that it can penetrate and destroy microscopic bacteria and viruses, but wouldn't travel through the protective outer layers of human skin or eyes.

“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 says. Previous research has also shown that far-UVC light can kill MRSA bacteria, a common cause of infections after surgery and a major problem in hospitals.

Now, Brenner and his colleagues have show that UVC light can effectively kill airborne influenza. In their new study, aerosolized particles of the H1N1 seasonal flu virus were released into a test chamber and exposed to very low doses of far-UVC light. The light inactivated the viruses with about the same efficiency as conventional germ-killing UV light, while a control group of bacteria not exposed to light remained alive.

“We think that this type of overhead light could [work] basically in any public setting,” says Brenner. “Think about doctor’s waiting rooms, schools, airports and airplanes—any place where there’s a likelihood for airborne viruses.” And unlike the flu vaccine, he says, far-UVC light is likely to be effective against all airborne microbes, including newly emerging virus strains.