Factcheck on UV Disinfection for COVID-19

Many regulatory authorities and bodies believe that UV disinfection technologies can play a role in a multiple barrier approach to reducing the transmission of the virus causing COVID-19, SARS-CoV-2, based on current disinfection data and empirical evidence. UV is a known disinfectant for air, water and surfaces that can help to mitigate the risk of acquiring an infection in contact with the COVID-19 virus when applied correctly.

Facts on the UV Disinfection and COVID-19

Can UVC help prevent COVID-19 transmission by reducing contamination?

For years, UVC light has been used extensively disinfecting drinking water, waste water, air, pharmaceutical products, and surfaces against a whole suite of human pathogens. All bacteria and viruses tested to date respond to UV disinfection. Some organisms are more susceptible to UVC disinfection than others, but all tested so far do respond at the appropriate doses.

UVC disinfection is often used with other technologies in a multibarrier approach to ensure that whatever pathogen is not killed by one method (say filtering or cleaning) is inactivated by another (UVC).

COVID-19 infections can be caused by contact with contaminated surfaces and then touching facial areas (less common than person-to-person, but still an issue). Minimizing this risk is key because COVID-19 virus can live on plastic and steel surfaces for up to 3 days. Normal cleaning and disinfection may leave behind some residual contamination, which UVC can treat suggesting that a multiple disinfectant approach is prudent. UVC has been shown to achieve a high level of inactivation of a near-relative of COVID-19s virus (i.e., SARS-CoV-1, tested with adequate dose of 254nm UV while suspended in liquid)

UV light, specifically between 200-280nm (UVC or the germicidal range), inactivates (aka, kills) at least two other coronaviruses that are near-relatives of the COVID-19 virus: 1) SARS-CoV-1 and 2) MERS-CoV. An important caveat is this inactivation has been demonstrated under controlled conditions in the laboratory. The effectiveness of UV light in practice depends on factors such the exposure time and the ability of the UV light to reach the viruses in water, air, and in the folds and crevices of materials and surfaces.

Are UVC disinfection devices safe?

Like any disinfection system, UVC devices must be used properly to be safe. They all produce varying amounts of UVC light in wavelengths of 200nm-280nm. This UVC light is much stronger than normal sunlight, and can cause a severe sunburn-like reaction to your skin. The target tissue in the eye would be the cornea (rather than the retina). The effect on the cornea is called photokeratitis, which is also known as welders flash or snow-blindness, is like a sunburn of the eye. Its unlikely that any of the UVC light would penetrate through the cornea and then lens to reach the retina because of the short wavelength (i.e. high frequency).

Some devices also produce ozone as part of their cycle, others produce light and heat like an arc welder, others move during their cycles. Hence, general machine-human safety needs to be considered with all disinfection devices, and these considerations should be addressed in the operations manual, in the user training, and appropriate safety compliance.

Are there performance standards and UVC validation protocols for UV disinfection devices?

Given the wide array of UVC devices marketed for disinfection of air, water and solid surfaces, the lack of uniform performance standards and the highly variable degree of research, development and validation testing that is performed on different devices, the IUVA urges consumers to exercise caution when selecting equipment and look for evidence of third party testing as well as certification of device materials and electrical components by well-known organizations such as NSF, UL, CSA, DVGW-OVGW or other international requirements as applicable.

For UVC devices designed to inactivate air and solid surfaces in the healthcare industry, members of IUVA are working diligently with other national standards organizations in the lighting and healthcare industry to develop disinfection testing standards. The goal is to develop guidance that will help healthcare providers world-wide choose the best possible technologies for their institutions to use in the fight against multiple drug resistant organisms and other pathogens, like the COVID-19 virus.