Shine Some Ultraviolet Light To Kill Influenza

A new Columbia University study reported low-doses of far-ultraviolet C (far-UVC) light can kill airborne influenza viruses, without harming humans.

In this study, far-UVC light efficiently inactivated airborne aerosolized viruses, with a very low dose of 2 mJ/cm2 of 222-nm light inactivating, up to 95 percent of aerosolized H1N1 influenza virus.

This study’s finding suggests deploying overhead far-UVC light in pharmacies, hospitals, doctors’ offices, schools, and airplanes to prevent spreading the influenza virus.

Healthcare providers believe people can catch the ‘flu’ by exposure to droplets from an infected person's coughs or sneezes, as well as when touching contaminated surfaces.

“If our results are confirmed in other settings, it follows that the use of overhead low-level far-UVC light in public locations would be a safe and efficient method for limiting the transmission and spread of airborne-mediated microbial diseases, such as influenza and tuberculosis,” David J. Brenner, Ph.D., with the Center for Radiological Research at Columbia University Irving Medical Center (CUIMC).

Broad-spectrum UV light, which has 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.

A key advantage of the UVC based approach, contrasted to vaccinations, is that UVC light is likely to be effective against different influenza strains, said these researchers.

In their earlier studies, Dr. Brenner’s team demonstrated that far-UVC light was effective at killing MRSA (methicillin-resistant S. aureus) bacteria, a common cause of surgical wound infections, but not harming human skin.

Hospitals and laboratories often use ultraviolet (UV) light to kill microbes but these can harm humans. UV lights disinfect by disrupting the molecular bonds that hold together microbial genetic material or proteins.

“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, Ph.D., the Higgins Professor of Radiation Biophysics at the Vagelos College of Physicians and Surgeons and director of the Center for Radiological Research at Columbia.

“Far-UVC light has a very limited range and cannot penetrate through the outer dead-cell layer of human skin or the cornea 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 Dr. Brenner.

“At a price of less than $1,000 per lamp, far-UVC lights are relatively inexpensive. And unlike flu vaccines, far-UVC is likely to be effective against all airborne microbes, even newly emerging strains,” Dr. Brenner added.

The study’s other contributors are David Welch, Manuela Buonanno, Veljko Grilj, Igor Shuryak, Connor Crickmore, Alan Bigelow, Gerhard Randers-Pehrson, and Gary Johnson (all at CUIMC).

The authors declared that they have no financial or other conflicts of interest. The study was supported by grants from the Shostack Foundation and the National Institutes of Health (1R41AI125006-01).

Columbia University Irving Medical Center provides international leadership in basic, preclinical, and clinical research; medical and health sciences education; and patient care.