Can UV light kill the coronavirus?
There have not been conclusive studies done to show whether or not UV light can kill coronavirus specifically, but based on evidence that it kills bacteria, fungi and viruses (including the flu,) presumably it is effective against coronavirus as well. The same team at Columbia that studied the flu has shown that UV light can eradicate two types of airborne seasonal coronaviruses and they are now testing SARS-CoV-2, so better data should be available soon. The high frequency of UV light kills microbes by damaging the DNA or RNA code and triggers mutations that prevent the micro-organisms from reproducing. The UV light in germicidal fixtures is not the sunburn-causing UVA and UVB light, but rather UVC light, which has shorter wavelengths than the others. Far-UVC light cannot reach or damage living human cells and is thus the technology being investigated for use in public spaces.
Currently, conventional germicidal UV lights are being used to sterilize unoccupied hospital rooms and subway cars, but there are other smaller permanent and portable devices that are potentially useful as well. You may have seen blue lights high on the wall in restaurants and airports before; these lights use technology called “upper-room ultraviolet germicidal irradiation” and there is hope that they could play a role in containing further spread of coronavirus if they can truly “zap pathogens out of the air in stores, restaurants and classrooms.” Various studies have shown UV light fixtures to be effective in disinfecting air in relatively small areas with good ventilation, so one of the challenges will be investigating the effectiveness in different settings. Dr. Srebric, a professor of mechanical engineering who is studying UV light said “I know it will definitely improve safety, but I cannot tell you by how much or how safe or whether I would go to a mall.” Amazon has built a robot that would be able to roll down the aisles in stores and warehouses to hopefully kill the virus on surfaces. There are also handheld devices such as those that sterilize cell phones and small personal items or wands that could be used to sterilize larger surfaces. Most of these products claim to kill 99.9% of bacteria and viruses, so odds are relatively good that coronavirus will also fall victim to UVC light. If you plan to use any of the consumer devices, please remember to follow the directions closely and never look at the light or use it directly on your skin and remember that hand-washing and other preventative measures should be continued as well.
(Jackie Phillips, MD, May 11, 2020)