Can UV Light Cure the Coronavirus?

No, it can’t. But that’s the wrong question. The real query is whether UV light can help in the fight against COVID-19. And the answer is a resounding “yes.”

Recently, President Trump pondered whether UV light could be sent inside the body to kill the coronavirus. And no, it can’t. That much UV light would do more harm than good, and it couldn’t penetrate deep enough to reach the affected organs.

But the politicized nature of (the government’s response to) COVID-19 obscures the fact that UV light has a long history in medicine.

A short primer – the sun is a G-type main-sequence star that burns at approximately 5,800°K and fuses 600 million tons of hydrogen into helium and converts 4 million tons of matter into energy every second.

Of that, the solar constant is 1,368 W/m² at the Earth’s atmosphere, and after attenuation, the sunlight that reaches the surface is about 1,000 W/m². Meanwhile, the ultraviolet (UV) rays are divided into three types – UV-A, UV-B, and UV-C. Most UV-A rays pass through the atmosphere, and the majority of UV-B rays are blocked, but both contribute to skin cancer (and UV-B stimulates the production of vitamin D). UV-C rays are completely absorbed by the atmosphere, and it’s this type (200-280 nm) that’s suitable for germicidal purposes.

But can they help in the coronavirus fight?

Regency Lighting points out that Germicidal UV products usually boast a 99.9% pathogen kill rate (equivalent to standard disinfecting wipes). It’s for this reason that UV light is often used to disinfect rooms and surfaces in hospitals, labs, senior care centers, fire and police stations, airports, and transit stations.

“Germicidal UV lights can actually change the DNA and RNA of bacteria and viruses, destroying their ability to reproduce,” the company notes. In this case, it wouldn’t actually kill viruses, but “inactivate” them.

What’s less clear is how effective UV light is against COVID-19, which is different than past viruses (as you might’ve surmised from the global quarantine). That said, coronaviruses generally fall into the category of "enveloped viruses" (or Class 3 on the tolerance scale to disinfectants). “Enveloped viruses” are supposedly the easiest to get rid of.

A team at the Center for Lighting Enabled Systems and Applications at Rensselaer Polytechnic Institute has developed a UV-C system designed to disinfect N95 masks, and the early returns are promising.

“There's no doubt we'll be able to deactivate the virus at the right dose,” said Bob Karlicek Jr., director of the center. “The question is how many uses can we get? Does the UV light damage the straps that hold the mask on the face?”

By the time you read this, the country may have begun to reopen, but I seriously doubt COVID-19 has been completely eradicated, so here’s hoping Germicidal UV devices will advance to the point where they’re a vital component of the coronoavirus fight.

Best Regards,

Jason Lomberg

North American Editor, PSD