Coronavirus has devastated the global economy and killed more than 270,000 people as it spread exponentially.
As conversations shift towards reopening the country and getting people back to work, proper sanitation in high traffic and public spaces will be key to getting back to normal.
In places like China, robots and drones are being used to spray disinfectant in public spaces. Airlines and companies like Amazon have been using fogging as a sanitation technique to keep their facilities clean.
But there is another option.
UV light is an effective disinfectant that has been used for decades in hospitals and operating rooms. The global UV disinfection equipment market was valued at $1.1 billion in 2018 and is projected to reach $3.4 billion by 2026.
President Trump recently brought up using ultraviolet light to fight the coronavirus.
(Video clip: President Trump: Supposing we hit somebody with a tremendous, whether it’s ultraviolet or just very powerful light. And I think you said that hasn’t been checked but you’re going to test it. And then I said, supposing you brought the light inside the body, which you can do either through the skin or in some other way. – Video ends.]
Though powerful UV light cannot be used on the human body, it can help prevent the spread of the virus. And technological breakthroughs could see UV light become a key piece in returning to normal in a world with a looming Covid-19 threat.
Ultraviolet light was discovered more than 200 years ago. It was first used for disinfecting surfaces in 1877, for water in 1910 and for air in 1935.
It was discovered because of its antimicrobial, antibacterial properties. And actually in health care became pretty widely adopted in an effort to try to disinfect the air and ensure that people who were in that environment were not getting exposed to tuberculosis.
UVC has been known for more than 100 years now to be really, really good at killing microbes, bacteria and viruses both.
Ultraviolet light is part of the electromagnetic spectrum, which includes things like gamma rays, x-rays, infrared light, microwaves, visible light and radio waves.
Ultraviolet light is grouped into three categories based on the light’s wavelength. There’s ultraviolet A, ultraviolet B and ultraviolet C. The sun produces all three types of UV radiation, but we only experience A and B on Earth’s surface.
UVC does not penetrate the clouds, so it doesn’t hit us here on Earth. UVA and UVB light do. That’s why people go outside and they can get sunburns and things like that. So everybody’s familiar with the power of ultraviolet light.
Within the spectrum of ultraviolet light, UVC, which sits at 200 to 280 nanometers, is in the germicidal disinfecting range.
What we experience as sunlight here on earth is mainly UVA and a little bit of UVB. And they are actually much less efficient at killing microbes than UVC. UVC is by far the more efficient way of killing microbes.
We know that ultraviolet light is effective against many different kinds of viruses, many types of bacteria and even some very hardy bacteria that can produce spores with thick coatings on them. Ultraviolet light can be effective against those and effective against fungus also.
UVC light can be quite dangerous. It can burn exposed skin and damage your retina. The World Health Organization issued guidance not to use UV lamps to sterilize hands or other parts of the skin.
The issue with UVC, though, is that it’s a health hazard. So you can really only use it when people are not around.
UVC light interferes with and destroys the nucleic acids, the DNA or RNA, of bacteria, viruses and other microbes.
What it does is it causes chemical bonds that aren’t supposed to be there to form within the genes of the microbe. And those new chemical bonds prevent the microbe from replicating. And because the microbe can’t replicate any longer, it effectively kills it off.
It breaks open the protein shell of a pathogen. So imagine a pathogen and everybody’s seen a cell under a microscope. Imagine it like an egg and you’re cracking an egg. And once you’ve cracked the egg, you can’t put the egg back together. That’s what we’re doing o n a microscopic level.
Ultraviolet light can kill microbes in many different environments. It has been used for several decades to disinfect drinking water, wastewater, air, pharmaceutical products and surfaces against the whole suite of human pathogens.
Despite all of its uses, there are a few things that limit its effectiveness.
If there is organic material, so if there’s essentially dirt on a surface, the dirt impacts how much of that ultraviolet C light is able to get to the microbes. And because of that, it works best if the surfaces are cleaned first and then the surfaces are exposed to the UVC light.
Another important point is that if you try to disinfect a room with UVC Light and you have, let’s say a telephone sitting on a bedside table, the area under that telephone is not going to be effectively decontaminated.
UVC light has been used to combat other coronaviruses such as MERS and SARS, and it was used against Ebola. It’s been proven effective and is expected to also work against the SARS-CoV-2, the virus that causes Covid-19.
Because we know it’s effective against the coronavirus family and there’s structural similarities between all of the viruses in the coronavirus family, everybody expects that ultraviolet C light will be very effective against the SARS-CoV-2 virus.
UVC light has been increasingly used in health care environments to prevent infections in hospitals.
As we started to see more drug resistant bacteria and drug resistant fungus, there is really a growing interest in the use of ultraviolet C light to help disinfect our health care environments.
Xenex is one company that built a UVC robot to sanitize hospital rooms. The company says its LightStrike robot is disinfecting somewhere in the world every 4.7 seconds.
Just in the United States, 2 million people a year go to the hospital and get an infection from going to the hospital. And then 100,000 of those 2 million die each year from those infections. In the hospitals that have used our robots, they’re dropping their infection rates 50%, 70%, even 100%.
That’s really what we focus on, is how do we reduce the infection rates and make it the hospitals a safer place for patients to go.
UV light is efficient as a disinfectant tool and it just needs electricity to work. As long as they have the robot and a box of bulbs, they can take energy, electricity and convert it into disinfection. It’s faster and less labor intensive than cleaning by hand. It also reduces the need to clean with powerful chemicals.
So you could just use more bland soaps for the cleaning and then rely on UVC for a chemical free disinfection. It’s hard to get to all the surfaces in a 15 or 20 minute room turnaround time.
The second thing is, is the chemicals end up being very corrosive on the surfaces. You need to leave surfaces visibly wet for several minutes to kill viruses. They’re only to be used on hard, non-porous surfaces and they’re also only to be used in well ventilated areas.
Cleaning staff can also miss areas.
There was a number of studies that came out in the early 2000s showing that housekeepers, and they do an incredible job. They would miss about half of the high touch surfaces.
One other thing that’s worth adding is there’s been recent publications that have demonstrated that in Italy, the hospitals actually became the agents of infection. So the hospitals were so pathogenic that they were passing the pathogen from patient to patient.
Ultraviolet light could be a powerful tool in the fight against Covid-19. And in some instances, it’s already being used. China is disinfecting entire buses with UV light and banks are using UVC on currency.