In an effort to combat the highly contagious novel coronavirus, people are turning to technology like ultraviolet light boxes and lamps to sanitize phones, masks, and other high-touch surfaces like doorknobs, light switches, and keys. Experts say that UV light may indeed kill the virus that causes COVID-19 — but there are many caveats. Before you buy a UV tool of your own, here's what you should know about how to use it safely and effectively.
Does UV Light Actually Kill the Coronavirus?
"While there is more research to do, ultraviolet C (UVC), a special type of ultraviolet light, has been shown to kill the virus that causes COVID-19 in laboratory-controlled experiments," Mark Cameron, PhD, associate professor at Case Western Reserve University School of Medicine, told POPSUGAR. Dr. Cameron explained that UVC is a short-wave version of the more familiar UVA and UVB lights, which can cause sunburns. "UVC works by degrading proteins on the surface of the virus, effectively killing it outright or destroying its ability to infect our cells and grow within," Dr. Cameron said.
Peter Gulick, DO, associate professor of medicine at Michigan State University, added that, while UVC is the most effective form of UV light for combatting pathogens, "it's also potentially toxic to skin and mucous membranes."
Should You Use UV Light to Disinfect Surfaces at Home?
Dr. Cameron explained that, with the exception of industrial settings, relying on UVC light alone to disinfect surfaces isn't practical and it should be preceded by other sanitization methods, such as household disinfectants. "A UVC device must deliver an effective dose of UV light to sterilize a surface, meaning enough power for enough time, [which is] usually minutes not seconds of exposure," Dr. Cameron said. He also noted that a UVC light won't be able to disinfect surfaces that are lying in shadows or under layers of dust, dirt, or other contamination.
If you do opt to use a UV light to sanitize high-touch surfaces at home, it's crucial to remember that UVC light must deliver a minimum "dose" in order to effectively kill viruses or bacteria on a surface. Dr. Cameron explained that the necessary exposure can range from five to 10 minutes for small items like phones to more than 20 minutes for larger items that have rough surfaces.
Again, Dr. Cameron emphasized the importance of using a UV light with caution. "If an item is heavily contaminated or shaped irregularly and the UVC light can't penetrate through layers of dirt or into shadowed areas, it won't be effectively cleaned," he explained. "Likewise, if the UVC light source is damaged or at the end of its useful life, it won't be effectively cleaned." That can happen more frequently than you might think. "UVC light sources have a finite lifespan and the bulbs must be maintained or replaced regularly to remain effective," Dr. Cameron said.
Due to these potential failures, Dr. Cameron said that you shouldn't rely on UVC sterilization alone. If at all possible, use other wipe-clean methods prior to exposing a high-touch surface to UVC light.
Are There Any Dangers to Using UV Light?
Both doctors stressed that it's important to be aware of the potential dangers before using a UVC light. "Direct exposure to UVC can cause burns to the skin and damage to the eyes," Dr. Cameron said. Dr. Gulick agreed, noting that UV light kills viruses and bacteria by causing defects in RNA and DNA. "It will kill COVID-19 by causing RNA defects, but it also can cause skin irritation, burns, and long-term cancer," Dr. Gulick told POPSUGAR. "It's also dangerous to eyes and other mucous membranes."
Lastly, Dr. Gulick pointed out that, as of publication, no standards have been devised to determine efficacy levels versus toxicity levels from UV light. However, "there may be a resurgence in looking at this concept, especially since we'll be indoors and [UVC light] may provide additional protection when coupled with masks — especially in restaurants, gyms, and classrooms," he said.
POPSUGAR aims to give you the most accurate and up-to-date information about the coronavirus, but details and recommendations about this pandemic may have changed since publication. For the latest information on COVID-19, please check out resources from the WHO, the CDC, and local public health departments.