Could UV lamps make light work of coronavirus?

Could a new type of ultraviolet lamp be used in stations, planes and schools to kill dangerous viruses, becoming a game changer in the Covid-19 fight?

Researchers at Columbia University have been working on such uses for years, and the current pandemic could confirm the value of their efforts.

Ultraviolet-C (UVC) lamps have long been used to kill bacteria, viruses and moulds, notably in hospitals and in the food-processing industry.

As the coronavirus pandemic knocks world economies on their heels, this technology is experiencing a boom.

But UVC rays are dangerous, causing skin cancer and eye problems, and can be used only when no one is present.

The New York subway system, following the example of Chinese subways, plans to use ultraviolet lamps to disinfect its trains, but only during nighttime closures.

A team at Columbia’s Centre for Radiological Research is experimenting with so-called far-UVC, rays whose wavelength of 222 nanometers makes them safe for humans but still lethal to viruses, the centre’s director, David Brenner, said.

At those frequencies, he said, the rays cannot penetrate the surface of the skin nor of the eye.

That means they could be used in closed and crowded spaces where contamination risks run high, with potentially huge promise for use during the pandemic.

In late April 2020, US President Donald Trump offered confusing remarks about somehow projecting ultraviolet rays into people’s bodies to kill the coronavirus.

He appeared to be inspired by federal research on the effects of natural light on the virus — but natural light has no UVC rays.

In 2013, the Columbia team began studying the effectiveness of far-UVC against drug-resistant bacteria.

Next it examined the rays’ use against viruses, including the flu virus. Only recently did it turn its attention to the coronavirus.

“We were thinking, how can we apply what we are doing to the current situation?” Brenner said.

But to test the effect of UVC on the extremely contagious coronavirus, the team had to move its equipment into a highly bio-secure laboratory at Columbia.

Experiments, which began “three-four weeks ago”, Brenner said, have already made it clear that UVC rays destroy the virus on surfaces within minutes.

The team plans to test the lamps on viruses suspended in the air, for coughs or sneezes.

In parallel, tests are being conducted to confirm that these rays are harmless to humans.

For 40 weeks the lab has exposed mice to far-UVC rays for “eight hours a day, five days a week, at intensities 20 times higher than we might think of using with humans”.

The far-UVC experiment at Colombia University. The virus is aerosolised at the left of the picture, flows across the window in the middle where it is exposed to the far-UVC light, and then collected on the right of the picture and assayed as to how many viruses are dead and how many alive
UNDER CLOUD OF DARKNESS: The far-UVC experiment at Colombia University. The virus is aerosolised at the left of the picture, flows across the window in the middle where it is exposed to the far-UVC light, and then collected on the right of the picture and assayed as to how many viruses are dead and how many alive
Image: MANUELA BUONANNO/ COLUMBIA UNIVERSITY/ AFP

The results?

After testing the rodents’ eyes and skin, “we have found absolutely nothing; the mice are very happy — and very cute as well,” Brenner said.

The experiment is set to continue for 20 more weeks.

The findings cannot be fully validated by the scientific community until all remaining steps have been taken, even if the team has already submitted its preliminary results to the journal Nature.

But the pressure to reopen the world’s economies has become so enormous that factories are accelerating their production of ultraviolet lamps without waiting.

“We really need something in situations like offices, restaurants, airplanes, hospitals,” Brenner said.

While UVC lamps have already been in commercial use for two or three years — notably in the diamond industry, where they can be used to distinguish artificial from genuine gems — potential clients are now legion, say companies producing them.

“We felt for a long time this is a great application for this technology,” John Yerger, the CEO of Eden Park Illumination, a small producer in Champaign, Illinois, said.

But with the pandemic, “the world has changed a lot in the last three months”.

And the US Food and Drug Administration has relaxed its regulation of tools or agents that can be used for disinfection, encouraging manufacturers to find a solution.

“There will be thousands and thousands of these things [UVC lamps] for sure,” Yerger said.

“The question is, will it be millions?”

Shinji Kameda, chief operations officer in the US for Japanese manufacturer Ushio,  said: “What we are seeing is a tremendous amount of customer interest” to produce lamps for airlines, cruise ships, restaurants, movie theatres and schools.” 

Production of its 222-nanometer lamps, sold for $500 (R9,200) to $800 and already used in some Japanese hospitals, will be stepped up in October, he said.

In the meantime, Brenner said he had been losing sleep.

“I spend nights thinking, if this far-UVC project had started one or two years earlier, maybe we could have prevented the Covid-19 crisis,” he said.

“Not completely, but maybe we could have prevented it being a pandemic.”

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