In a pandemic, people grow desperate for cures, so it’s no surprise that the worldwide outbreak of COVID-19 has people searching for anything that might protect them. Where there’s demand, supply quickly follows, and there are plenty of people online offering dubious supplements or tools to help ward off what is commonly known as the coronavirus. Among the most popular are UV sanitizing wands, which promise to annihilate germs easily using ultraviolet radiation.
They say sunlight’s the best disinfectant, but should you fill your Amazon cart with UV wands, or stick to soap and water? For answers, we spoke to Kim Trautman, executive vice president of medical device services at NSF International, a product testing, inspection, and certification organization. Trautman has decades of experience, having written the Food and Drug Administration’s (FDA) Quality Systems Regulations for medical devices.
What does UV light do?
Ultraviolet light is a type of electromagnetic radiation. One particular subtype, called UV-C (which has a wavelength of 280-100 nanometers), is capable of damaging viruses and bacteria (and human tissue) by disrupting their DNA/RNA, rendering them unable to replicate. In response to the pressure from the COVID-19 outbreak, hospitals are using large UV lamps (sometimes attached to robots) to sterilize rooms.
The problems with UV light as a disinfectant
If it’s good enough for hospitals, it’s probably good enough for your home, right? Not quite. There are a number of problems with using a UV wand to clean your home. For starters, UV-C radiation won’t be too helpful unless you live in a bare room.
“Most of the science shows that the effectiveness of UV-C light is really on more flat surfaces,” Trautman says. “It does not do well in nooks and crevices because it’s a spectrum of visible light, and if the light can’t get in, it’s not going to have the same effect. So if you’ve got crooks and crannies, then those germs in those crooks and crannies are not going to be affected by the UV-C light.”
Then there’s a problem of scale: A UV wand can only cover a small surface area, so if you were to try and disinfect a whole room, you’d probably be at it for a while.
“If you see a picture of some of the hospital units that have been used for this purpose,” Trautman explains, “they’re very, very large. They’re not just a handheld wand-type thing. You have to have something that sits in the right position in the room that’s going to be able to radiate. If it doesn’t radiate 360 degrees, then it’s going to have to have some sort of rotational mechanism” to ensure the entire room gets treated.
A hazard to your health
Among the many problems with using a UV wand to disinfect, Trautman emphasizes the danger UV-C light poses to human flesh.
“As much as UV-C light can degrade cell walls, proteins, and membranes of bacteria and viruses,” she says, “it also is carcinogenic, or can cause cancer affecting humans. It’s the spectrum of UV light that does give us sunburns. So exposure to human skin, to the eyes, and so forth can be very detrimental. So it’s not something to be done lightly.”
Those robots blasting hospital rooms are doing so when there are no people inside. By its very nature, a UV wand requires someone to hold it. Looking through some of the UV wands available on Amazon, none of them seem to include protective equipment, although one did specify that customers should wear protective glasses while using it. If the device is capable of destroying viruses, it’s also capable of hurting you.
“If you’re waving it around and there’s no way to protect you, you’re probably doing more harm to yourself than the potential of what you’re disinfecting,” Trautman says.
When it comes to coronavirus, the science isn’t there yet
Another problem with using UV radiation as a disinfectant is that we’re simply not yet sure how effective it is at killing COVID-19 specifically. When using UV radiation, “the duration of direct exposure is important,” says Trautman. “It’s not just … a flash of the light. It does have to have direct UV-C light for a specific period of time, depending on the distance from the source and so forth.”
The precise duration necessary can vary not just on the light source, but on the virus you’re trying to eradicate, and all viruses are not made equally. Some are more susceptible to UV radiation, others are tougher, and there is no scientific consensus as to how sturdy the coronavirus is.
“We already know that it’s a little bit more robust than some of the earlier varieties [of coronaviruses]” Trautman explains. “Some of the earlier varieties of SARS died much quicker on surfaces. We already know that with cardboard, glass, plastics, COVID-19 is lasting longer on some of the surfaces than some of the previous variations of this family of viruses. There’s no specific scientific studies yet that can definitively say what the time and duration of UV-C exposure would be necessary to prove that COVID-19 has been disassembled enough to be non-potent or nonreplicating.”
When in doubt, trust the health authorities
With the flood of UV gadgets on the internet, it’s important to note that many of them go to market without approval from health authorities.
“For the most part,” Trautman says, “if UV lights are being used for things that don’t have medical claims, the FDA does not get involved. I’ve seen a whole bunch of these UV-C containers that they say to put your cell phones in. The FDA is not getting involved in those types of commercial claims.”
Even if the UV wands are functional, however, the cons outweigh their usefulness: UV light is only suited to flat surfaces, you can’t know how long you need to disinfect a surface to kill coronavirus, and you may end up hurting yourself in the process.
What to do if you’re worried about coronavirus on your countertops? Trautman’s advice is to trust the Centers for Disease Control and Prevention (CDC), which has guidelines for people to disinfect at home.
“Anything else is pure speculation and the science is not there,” Trautman said.
For the latest updates on the novel coronavirus outbreak, visit the World Health Organization’s COVID-19 page.