More on: Does UV-C Kill SARS-CoV-2?

Does UV-C Kill SARS-CoV-2?

Yes. SARS-CoV-2 being a relatively new virus (hence ‘novel’) there are not yet 100’s of proper scientific papers confirming this, BUT on top of indeed 100’s that confirm efficacy against various Corona viruses, there are a growing number that look specifically at SARS-CoV-2:

Susceptibility of SARS-CoV-2 to UV irradiation

Most noteworthy:

  • SARS-CoV-2 is highly susceptible to irradiation with ultraviolet light.
  • High viral loads of 5 * 106 TCID50/ml SARS-CoV-2 can be inactivated in 9 minutes by UVC irradiation.
  • UVC irradiation represents a suitable disinfection method for SARS-CoV-2.

“The coronavirus SARS-CoV-2 pandemic became a global health burden. We determined the susceptibility of SARS-CoV-2 to irradiation with ultraviolet light. The virus was highly susceptible to ultraviolet light. A viral stock with a high infectious titer of 5 × 106 TCID50/mL was completely inactivated by UVC irradiation after nine minutes of exposure. The UVC dose required for complete inactivation was 1,048 mJ/cm2. UVA exposure demonstrated only a weak effect on virus inactivation over 15 minutes. Hence, inactivation of SARS-CoV-2 by UVC irradiation constitutes a reliable method for disinfection purposes in health care facilities and for preparing SARS-CoV-2 material for research purpose.”

Authoring Committee: IES Photobiology Committee
This Committee Report has been prepared by the IES Photobiology Committee in response to the 2020 COVID-19 pandemic, with the specific goal of providing objective and current information on germicidal ultraviolet irradiation (UVGI) as a means of disinfecting air and surfaces.

Most noteworthy:

“ Yes, if the virus is directly illuminated by UV-C at the effective dose level. UV-C can play an effective role with other methods of disinfection, but it is essential that individuals be protected to prevent UV hazards to the eyes and skin as elaborated in Section 4. UV-C should not be used to disinfect the hands!”

Light-based technologies for management of COVID-19 pandemic crisis

J Photochem Photobiol B. 2020 Nov; 212: 111999.

Most noteworthy:

“In a recent study, Fischer et al. showed that UV-C light can inactivate more than 99.9% of SARS-CoV-2 viral particles deposited over the filtering material of N95 masks and stainless steel surface [38]. As expected, inactivation kinetics over stainless steel was much faster (i.e., more than 99.9% for (0.33 J/cm2). However, after sufficient exposure (1.98 J/cm2) UV-C could promote germicidal efficacy levels that were similar to those promoted by ethanol, dry heat or vaporized hydrogen peroxide. Older studies have hypothesized that the necessary dose to inactivate 90% of viruses present in N95 filtering facepiece respirator (FFR) material would be about 30 times higher than over the surface of non-porous materials [39]. This was an interesting estimation, but we should keep in mind that UV-C emission spectrum and irradiance of different UV-C equipment as well as material composition are widely variable [40]. Therefore, such estimatives cannot be used as a robust procedure and experimental demonstrations must always be presented. Indeed, a recent in silico study demonstrated that for effective and fast decontamination one should consider the FFR shape besides the optical properties of the FFR model, which has to be determined at the UV-C specific wavelength [41]. Even though UV does not seem to affect the filtrating capacity of FFRs, it is important to note that high UV-C doses can lead to reduced tensile strength of its materials [42,43].”

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