Far-UVC light: Lethal to bacteria & viruses but safe for humans?

May 24, 2019

Last year, there were reports of a UV light device that could kill airborne influenza. This device was also reported to have no ill effects on human cells after prolonged exposure to the UV rays. The lamp that had been tested used far- UVC light (207–222 nm) which appears to inactivate bacteria whilst being safe for use around humans. The buzz around this and subsequent news reports that were published came about in February 2018. Since then, has the safer UV light become a reality?

UV lights have been used to eradicate bacteria in hospitals for a while now but this had to be done when there were no people in the room due to potential dangerous side effects of prolonged UV light exposure. Due to this, the promise of a UV light that killed airborne viruses whilst people could stay in the room seemed remarkable and groundbreaking.

It is claimed that far- UVC light is not harmful to humans as it cannot penetrate human skin or eyes. Due to the smaller size of bacteria and viruses, these can be penetrated and therefore inactivated.1 If humans are exposed to UV light for long periods, there is a risk of skin cancer or cataracts but at the far-UVC light wavelength, this doesn't seem to be the case.2

Research suggests that low dose, filtered far- UVC light in indoor spaces is economical, safe and effective at stopping the spread of airborne bacterial and viral infections. The experiment yielded very positive results with more than 95% of airborne H1N1 influenza inactivated by low dosage far-UVC light.3 As well as this, the findings also refer to the inactivation of drug resistant bacteria.4 This research reveals encouraging data that could potentially even help in the case of a pandemic.

As well as being placed within a room for long periods to prevent the spread of inection, another research paper published in the same month revealed how Far - UVC light could be used to prevent infection in open surgical wounds. Surgical wounds can become infected by airborne bacteria. The idea is that the far - UVC light is directed over the surgical wound. Any lamp used for this purpose would need to include a filter to prevent light being emitted at a greater wavelength which could be harmful.5 As well as protecting the patient, using these lamps during surgery instead of standard UV lamps means that the surgical team will not need to use protective equipment for themselves.6

How can all of this be put into practice? There are already several products on the market utilising these new findings. A quick internet search reveals that a couple of manufacturers and a few retailers are already promoting far- UVC technology. The products on offer include standalone lamps, robotic instruments, boxes that you can place items in and HVAC system lamps. We could only find products by two manufacturers which suggests that this technology although feasible and seemingly in use, has not hit the mainstream yet. However, for far- UVC products to be available to purchase just over a year after the research was published suggests that the use of far - UVC light in hospitals and other public spaces could be a regular occurance in the near future.

1, 4. Welch, D., Buonanno, M., Grilj, V., Shuryak, I., Crickmore, C., Bigelow, A.W., Randers-Pehrson, G., Johnson, G.W., Brenner, D.J. (2018) Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases, Scientific Reports 8, Article number: 2752

2 & 3. https://www.laserfocusworld.com/lasers-sources/article/16555364/uv-sterilization-faruvc-light-kills-airborne-flu-viruses-without-danger-to-humans

5, 6. Ponnaiya, B., Buonanno, M., Welch, D., Shuryak, I., Randers-Pehrson, G., Brenner, D.J. (2018) Far-UVC light prevents MRSA infection of superficial wounds in vivo, PLoS ONE 13(2): e0192053

Photo by Sacha Nouviale on Unsplash