As many readers know, we have been using UVC light to provide an extra coronavirus sterilization step for exam rooms and to add yet another layer of protection for our patients. One of my patients recently bought a $99 UVC wand off Amazon and asked during a Facebook Live if it would work to sterilize a hotel room. So could this thing put out enough light to kill anything?
What is UVC Light and Why Is It Important for Fighting COVID-19?
UVC light is part of the UV spectrum that’s been shown to kill viruses and bacteria. Because of that fact, it was often used by hospitals pre-pandemic to sterilize hospital ICUs and kill bad bugs like MRSA and. c Difficile. Post-pandemic, it’s also been shown to kill the coronavirus, so it’s being used in hospitals even more. In addition, this fact has spawned a huge number of cheap products on Amazon purporting to kill “viruses”.
How Can You Test if these Products Work?
Whether these UVC light products work all depends on how much power they can deliver to the surface you want to have sterilized. The math and physics behind how that’s calculated is complex and gave me a headache, so I bought UVC dosimeter cards. They have a photochemical that turns colors based on different levels of UVC light exposure. They’re designed for healthcare settings so they have two indicator colors, one for MRSA (50 mj/cm2) and one for C. difficile (100 mj/cm2). Hence, these cards are the rubber meets the road on whether the light is powerful enough to kill bad bugs.
In This Corner…
This is the UVC light I bought off Amazon. There are literally dozens of sellers who all seem to be selling this same exact battery-operated wand. You simply turn it on and you’re ready to rock and roll. I envisioned this thing being larger and brighter and blasting viruses in seconds. However, based on what I got sent, I have to say I was underwhelmed.
So could this thing with 12 LED UVC emitters actually sterilize pillows, bedsheets, or a hotel couch? Maybe the odd plane seat? Or maybe even the tabletop in a restaurant? While you would look like a serious nerd, in this time of COVID it seems like many things are getting a societal pass.
I wanted to give the wand the benefit of the doubt, so I held it directly over one of the dosimeter cards and started my stopwatch. It took a long three and a half minutes with no movement to reach the minimum hospital kill range for MRSA bacteria. While the coronavirus doesn’t do well in direct sunlight, I figured that this power zone was the minimum level that I would accept.
Based on my initial tests, I would estimate that it would take about 10 minutes of slowly moving this thing over the average pillow to sterilize one side. If you add up the time it would take to disinfect the average hotel room, you could spend an hour or two just disinfecting the common areas. So for me, this wand isn’t very practical.
I’ll be testing this wand with real bacteria in the lab later this week, so we’ll see how it tests out on that real-world test. So while it really didn’t pass muster with hospital disinfection standards, it could with its ability to actually kill living microorganisms.
The upshot? While this wand may not be practical to kill the coronavirus during travel, I have a few better ideas of how to disinfect a hotel room with UVC light that I’ll share in later blogs. In the meantime, the wand was just a bit too wimpy to live up to its claims on Amazon!