A technique that zaps airborne viruses with a narrow-wavelength band of UV light shows promise for curtailing the person-to-person spread of COVID-19 in indoor public places.

The technology, developed by Columbia University’s Center for Radiological Research, uses lamps that emit continuous, low doses of a particular wavelength of ultraviolet light, known as far-UVC, which can kill viruses and bacteria without harming human skin, eyes and other tissues, as is the problem with conventional UV light.

“Far-UVC light has the potential to be a ‘game changer,’” said David Brenner, professor of radiation biophysics and director of the center. “It can be safely used in occupied public spaces, and it kills pathogens in the air before we can breathe them in.”

The research team’s experiments have shown far-UVC effective in eradicating two types of airborne seasonal coronaviruses (the ones that cause coughs and colds). The researchers are now testing the light against the SARS-CoV-2 virus in collaboration with Thomas Briese and W. Ian Lipkin of the Center for Infection and Immunity in a biosafety laboratory on Columbia’s medical center campus, with encouraging results, Brenner said. 

The team previously found the method effective in inactivating the airborne H1N1 influenza virus, as well as drug-resistant bacteria. And multiple, long-term studies on animals and humans have confirmed that exposure to far-UVC does not cause damage to the skin or eyes.

If widely used in occupied public places, far-UVC technology has the potential to provide a powerful check on future epidemics and pandemics, Brenner said. He added that even when researchers develop a vaccine against the virus that causes COVID, it will not protect against the next novel virus.

“Our system is a low-cost, safe solution to eradicating airborne viruses minutes after they’ve been breathed, coughed or sneezed into the air,” Brenner said. “Not only does it have the potential to prevent the global spread of the virus that causes COVID-19, but also future novel viruses, as well as more familiar viruses like influenza and measles.”

Brenner envisions the use of safe overhead far-UVC lamps in a wide range of indoor public spaces. The technology, which can be easily retrofitted into existing light fixtures, he said, could be deployed in hospitals and doctors’ offices as well as schools, shelters, airports, airplanes and other transportation hubs.

Scientists have known for decades that germicidal UV light (wavelength around 254 nm) has the capacity to kill viruses and bacteria. Hospitals and laboratories often use germicidal UV light to sterilize unoccupied rooms, as well as other equipment. But conventional germicidal UV light cannot be used in the presence of people as it can causes health problems to the skin and eyes.

In contrast, far-UVC light, which has a very short wavelength (in the range from about 205 to 230 nm), cannot reach or damage living human cells. But these wavelengths can still penetrate and kill very small viruses and bacteria floating in the air or on surfaces.

Far-UVC lamps are now in production by several companies, although ramping up to large-scale production, as well as approval by the Food and Drug Administration and Environmental Protection Agency, will take several months. At between $500 and $1000 per lamp, the lamps are relatively inexpensive, and once they are mass produced the prices would likely fall, Brenner said.

“Far-UVC takes a fundamentally different tactic in the war against COVID-19,” Brenner said. “Most approaches focus on fighting the virus once it has gotten into the body. Far-UVC is one of the very few approaches that has the potential to prevent the spread of viruses before they enter the body.”