FACTS ABOUT UV-C DISINFECTION & STERILIZATION
The International Ultraviolet Association (IUVA) believes 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. "The IUVA has assembled leading experts from around the world to develop guidance on the effective use of UV technology, as a disinfection measure, to help reduce the transmission of COVID-19 virus. Established in 1999, the IUVA is a nonprofit dedicated to the advancement of ultraviolet technologies to help address public health and environmental concerns," says Dr. Ron Hofmann, Professor at the University of Toronto, and President of the IUVA.
FACTS ON UV-C LIGHT AND COVID-19
Can UVC help prevent COVID-19 transmission by reducing contamination?
Based on existing evidence, we believe so. UV-C light has been used extensively for more than 40 years in disinfecting drinking water, waste water, air, pharmaceutical products, and surfaces against a whole suite of human pathogens. All bacteria and viruses tested to date (many hundreds over the years, including other coronaviruses) respond to UV disinfection. Some organisms are more susceptible to UV-C disinfection than others, but all tested so far do respond at the appropriate doses.
UV-C 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 (UV-C). In this way UV-C could be installed now in clinical or other settings to augment existing processes or to shore up existing protocols where these are exhausted by excessive demands due to the pandemic. UV light, specifically between 200-280nm[i] (UV-C 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[ii] and 2) MERS-CoV[iii] [iv] [v]. 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 as 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. 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)[vi]. Minimizing this risk is key because COVID-19 virus can live on plastic and steel surfaces for up to 3 days[vii]. Normal cleaning and disinfection may leave behind some residual contamination, which UV-C can treat suggesting that a multiple disinfectant approach is prudent. UV-C has been shown to achieve a high level of inactivation of a near-relative of COVID-19’s virus (i.e., SARS-CoV-1, tested with adequate dose of 254nm UV while suspended in liquid)[viii]. IUVA believes similar results can be expected when treating COVID-19’s virus, SARS-CoV-2. However, the key is applying UV-C in such a way that it can effectively reach any remaining viruses on those surfaces. IUVA also concurs with CDC guidance to hospitals that the germicidal effectiveness of UV-C is influenced by the UVC absorbing properties of the suspension, the surface or aerosol that the organism is in; by the type or action spectra of the microorganism; and by a variety of design and operating factors that impact the delivered UV dose to the microorganism (link ). IUVA recognizes that in the cases where the UV-C light cannot reach a particular pathogen, that pathogen will not be disinfected. However in general, reducing the total number of pathogens reduces the risk of transmission. The total pathogenic load can be reduced substantially by applying UV to the many surfaces that are readily exposed, as a secondary barrier to cleaning, especially in hurried conditions. This would be a relatively straight-forward matter of illuminating the relevant surfaces with UV-C light, for example the air and surfaces around/in rooms and personal protective equipment.
