The Inactivation of SARS-CoV-2 in Critical Hospital Settings by Means of Ultraviolet C Lamps: Examples of Their Use and Some Practical Advice

Abstract Background UltraViolet-C (UV-C) lamps may be used to supplement current hospital cleaning and disinfection of surfaces contaminated by SARS-CoV-2. Our aim is to provide some practical indications for the correct use of UV-C lamps. Methods We studied three UV-C lamps, measuring their spatial irradiance and emission over time. We quantify the error that is committed by calculating the irradiation time based exclusively on the technical data of the lamps or by making direct irradiance measurements. Finally, we tested specific dosimeters for UV-C. Results Our results show that the spatial emission of UV-C lamps is strongly dependent on the power of the lamps and on the design of their reflectors. Only by optimizing the positioning and calculating the exposure time correctly, is it possible to dispense the dose necessary to obtain SARS-CoV-2 inactivation. In the absence of suitable equipment for measuring irradiance, the calculated irradiation time can be underestimated. We therefore consider it precautionary to increase the calculated times by at least 20%. Conclusion To use UV-C lamps effectively, it is necessary to follow a few simple precepts when choosing, positioning and verifying the lamps. In the absence of instruments dedicated to direct verification of irradiance, photochromic UV-C dosimeters may represent a useful tool for easily verifying that a proper UV-C dose has been delivered.

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Photochemical treatment of organic constituents and bacterial pathogens from synthetic slaughterhouse wastewater by combining vacuum-UV and UV-C

10.32920/ryerson.14643972.v1 ◽

2021 ◽

Author(s):

Mauricio Barrera

Keyword(s):

Vacuum Ultraviolet ◽

Irradiation Time ◽

Removal Rates ◽

Slaughterhouse Wastewater ◽

Toc Removal ◽

Short Period ◽

Bacteria Inactivation ◽

Ultraviolet C ◽

Inactivation Efficiency ◽

Uv C

The reduction and degradation of total organic carbon (TOC) and bacteria inactivation efficiency using Vacuum-Ultraviolet (VUV) oxidation process Ultraviolet-C (UV-C) photolytic process, and their combination (UV-C/VUV and VUV/UV-C) from synthetic slaughterhouse wastewater was investigated. TOC removal rates achieved during continuous mode operation were 6.2%, 5.5%, 5.8%, and 6.1%, respectively. In a second stage, H₂O₂ was added to both processes, UV-C/H₂O₂ and VUV/H₂O₂, and it was found that TOC removal rates were increased twice as much during continious flow operation to 10.8% and 12.2%, respectively. The optimum molar ration of H₂O₂/TOC was found to be 2.5 and 1.5 for each process respectively. Finally, it was observed that all photochemical processes achieved over 99.999% (five logs) of bacteria inactivation in a short period of irradiation time, 27.6 sec.

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EVALUATION OF GERMICIDAL UV-C LIGHT FOR SURFACE DISINFECTION IN A TERTIARY CARE HOSPITAL

Pakistan Armed Forces Medical Journal ◽

10.51253/pafmj.v71i3.5894 ◽

2021 ◽

Vol 71 (3) ◽

pp. 889-94

Author(s):

Qanita Fahim ◽

Nasir Uddin ◽

Najam Ul Hassan ◽

Nargis Sabir ◽

Anum Tariq ◽

...

Keyword(s):

Exposure Time ◽

Tertiary Care ◽

Military Hospital ◽

Care Hospital ◽

Archaeal Species ◽

Quasi Experimental ◽

Ultraviolet C ◽

Micro Organisms ◽

Uv C ◽

Safety Guidelines

Objective: To check the efficacy of 36-Watt Ultraviolet-C tube light, in terms of distance and time against medically important microorganisms (Staphylococcus aureus, Escherichia coli, Pseudomonas aeroginosa, Candida albicans and Aspergillus species). Study Design: Quasi-experimental study. Place and Duration of Study: Pathology department, Combined Military Hospital, Lahore Pakistan, from Jun to Sep 2020. Methodology: ATCC control organisms of above mentioned bacteria, yeasts, and fungi were exposed to ultraviolet-C light for different times and distances to ascertain its germicidal effect. Two methods were selected, one in which micro-organisms inoculated plates were exposed to ultraviolet-C light and second in which McFarland suspensions of microorganisms were exposed before inoculation. Both the methods were compared. Observations were noted down after repeated performance of both the procedures. Results: An exposure time of 15 minutes, mean ± SD (13.8 ± 10.1) at 1-foot distance was proved ideal for all the tested bacteria, but yeasts and fungi required >30 minutes, mean ± SD (17.5 ± 13.5) to be killed. Moreover, distance and time of exposure were found out to be directly proportional irrespective of microbial load. Greater the distance longer the ultraviolet C exposure was required. Conclusion: Ultrviolet-C light 36-Watt can have efficient inactivation of bacterial, fungal and archaeal species up to 6 feet for >30 minutes exposure time. Ultraviolet-C light disinfection is best for areas like closed rooms, operation theatres, PCR Labs, and bio-safety cabinets keeping bio-safety guidelines in view.

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Decontamination of Intravaginal Probes Infected by Human Papillomavirus (HPV) Using UV-C Decontamination System

Journal of Clinical Medicine ◽

10.3390/jcm8111776 ◽

2019 ◽

Vol 8 (11) ◽

pp. 1776

Author(s):

Pichon ◽

Lebail-Carval ◽

Billaud ◽

Lina ◽

Gaucherand ◽

...

Keyword(s):

Human Papillomavirus ◽

Second Phase ◽

Vaginal Ultrasound ◽

Human Dna ◽

Ensure Patient Safety ◽

Ultraviolet C ◽

Cleaning And Disinfection ◽

Uv C ◽

Step Study ◽

Ultrasound Probes

Background: This three-step study evaluated ultraviolet-C (UV-C) efficacy against human papillomavirus (HPV) found on vaginal ultrasound probes. Methods: The first two steps evaluated UV-C disinfection of vaginal ultrasound probes in routine condition. During the first phase, the probe (n = 100) was sampled after a complete cleaning and disinfection protocol, i.e., cleaning with chemically impregnated wipes, followed by UV-C. During the second phase, the probe (n = 47) was sampled after cleaning and UV-C. The final step consisted of applying mixes of HPV on a dedicated, covered probe (n = 15) then sampling the cover, the probe after removal of the cover, after cleaning, and after UV-C. HPV detection was performed using CLART® HPV2 PCR (Genomica, Madrid, Spain). Results: In the first phase, no probes were found to be positive for both DNA after UV-C. In the second phase, eight probes were found to be positive after cleaning (seven with human DNA and one with HPV) and negative after UV-C. In the final phase, one probe was found to be positive for HPV for each sample except after UV-C. Conclusions: Covers followed by a chemically impregnated wipe are not sufficient to ensure patient safety during vaginal ultrasound examinations. UV-C is effective in routine conditions against contaminations found on vaginal ultrasound probes, especially HPV.

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Photochemical treatment of organic constituents and bacterial pathogens from synthetic slaughterhouse wastewater by combining vacuum-UV and UV-C

10.32920/ryerson.14643972 ◽

2021 ◽

Author(s):

Mauricio Barrera

Keyword(s):

Vacuum Ultraviolet ◽

Irradiation Time ◽

Removal Rates ◽

Slaughterhouse Wastewater ◽

Toc Removal ◽

Short Period ◽

Bacteria Inactivation ◽

Ultraviolet C ◽

Inactivation Efficiency ◽

Uv C

The reduction and degradation of total organic carbon (TOC) and bacteria inactivation efficiency using Vacuum-Ultraviolet (VUV) oxidation process Ultraviolet-C (UV-C) photolytic process, and their combination (UV-C/VUV and VUV/UV-C) from synthetic slaughterhouse wastewater was investigated. TOC removal rates achieved during continuous mode operation were 6.2%, 5.5%, 5.8%, and 6.1%, respectively. In a second stage, H₂O₂ was added to both processes, UV-C/H₂O₂ and VUV/H₂O₂, and it was found that TOC removal rates were increased twice as much during continious flow operation to 10.8% and 12.2%, respectively. The optimum molar ration of H₂O₂/TOC was found to be 2.5 and 1.5 for each process respectively. Finally, it was observed that all photochemical processes achieved over 99.999% (five logs) of bacteria inactivation in a short period of irradiation time, 27.6 sec.

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Effectiveness of Ultraviolet-C Room Disinfection on Preventing Healthcare-Associated Clostridioides difficile Infection

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.512 ◽

2020 ◽

Vol 41 (S1) ◽

pp. s33-s33

Author(s):

Michihiko Goto ◽

Erin Balkenende ◽

Gosia Clore ◽

Rajeshwari Nair ◽

Loretta Simbartl ◽

...

Keyword(s):

Acute Care ◽

Acute Care Hospitals ◽

Incidence Rates ◽

Positive Test ◽

Negative Binomial Regression Model ◽

Test Results ◽

Clostridioides Difficile ◽

Ultraviolet C ◽

Healthcare Associated ◽

Uv C

Background: Enhanced terminal room cleaning with ultraviolet C (UVC) disinfection has become more commonly used as a strategy to reduce the transmission of important nosocomial pathogens, including Clostridioides difficile, but the real-world effectiveness remains unclear. Objectives: We aimed to assess the association of UVC disinfection during terminal cleaning with the incidence of healthcare-associated C. difficile infection and positive test results for C. difficile within the nationwide Veterans Health Administration (VHA) System. Methods: Using a nationwide survey of VHA system acute-care hospitals, information on UV-C system utilization and date of implementation was obtained. Hospital-level incidence rates of clinically confirmed hospital-onset C. difficile infection (HO-CDI) and positive test results with recent healthcare exposures (both hospital-onset [HO-LabID] and community-onset healthcare-associated [CO-HA-LabID]) at acute-care units between January 2010 and December 2018 were obtained through routine surveillance with bed days of care (BDOC) as the denominator. We analyzed the association of UVC disinfection with incidence rates of HO-CDI, HO-Lab-ID, and CO-HA-LabID using a nonrandomized, stepped-wedge design, using negative binomial regression model with hospital-specific random intercept, the presence or absence of UVC disinfection use for each month, with baseline trend and seasonality as explanatory variables. Results: Among 143 VHA acute-care hospitals, 129 hospitals (90.2%) responded to the survey and were included in the analysis. UVC use was reported from 42 hospitals with various implementation start dates (range, June 2010 through June 2017). We identified 23,021 positive C. difficile test results (HO-Lab ID: 5,014) with 16,213 HO-CDI and 24,083,252 BDOC from the 129 hospitals during the study period. There were declining baseline trends nationwide (mean, −0.6% per month) for HO-CDI. The use of UV-C had no statistically significant association with incidence rates of HO-CDI (incidence rate ratio [IRR], 1.032; 95% CI, 0.963–1.106; P = .65) or incidence rates of healthcare-associated positive C. difficile test results (HO-Lab). Conclusions: In this large quasi-experimental analysis within the VHA System, the enhanced terminal room cleaning with UVC disinfection was not associated with the change in incidence rates of clinically confirmed hospital-onset CDI or positive test results with recent healthcare exposure. Further research is needed to understand reasons for lack of effectiveness, such as understanding barriers to utilization.Funding: NoneDisclosures: None

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Output Reduction over Time of Germicidal UV-C Lamps Used for Treating Agricultural Crops

LEUKOS The Journal of the Illuminating Engineering Society of North America ◽

10.1080/15502724.2021.1921594 ◽

2021 ◽

pp. 1-9

Author(s):

Mark S. Rea ◽

John D. Bullough ◽

Andrew C. Bierman

Keyword(s):

Agricultural Crops ◽

Uv C ◽

Over Time

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Ultraviolet-C as a Viable Reprocessing Method for Disposable Masks and Filtering Facepiece Respirators

Polymers ◽

10.3390/polym13050801 ◽

2021 ◽

Vol 13 (5) ◽

pp. 801

Author(s):

Talita Nicolau ◽

Núbio Gomes Filho ◽

Andrea Zille

Keyword(s):

Literature Review ◽

Systematic Literature Review ◽

Personal Protective Equipment ◽

State Of The Art ◽

Protective Equipment ◽

Multiple Methods ◽

Ultraviolet C ◽

Single Use ◽

Uv C ◽

New Strategies

In normal conditions, discarding single-use personal protective equipment after use is the rule for its users due to the possibility of being infected, particularly for masks and filtering facepiece respirators. When the demand for these protective tools is not satisfied by the companies supplying them, a scenario of shortages occurs, and new strategies must arise. One possible approach regards the disinfection of these pieces of equipment, but there are multiple methods. Analyzing these methods, Ultraviolet-C (UV-C) becomes an exciting option, given its germicidal capability. This paper aims to describe the state-of-the-art for UV-C sterilization in masks and filtering facepiece respirators. To achieve this goal, we adopted a systematic literature review in multiple databases added to a snowball method to make our sample as robust as possible and encompass a more significant number of studies. We found that UV-C’s germicidal capability is just as good as other sterilization methods. Combining this characteristic with other advantages makes UV-C sterilization desirable compared to other methods, despite its possible disadvantages.

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Inactivation of Candida auris and Candida albicans by Ultraviolet-C

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.868 ◽

2020 ◽

Vol 41 (S1) ◽

pp. s292-s292

Author(s):

William Rutala ◽

Hajime Kanamori ◽

Maria Gergen ◽

Emily Sickbert-Bennett ◽

David Jay Weber

Keyword(s):

Infection Prevention ◽

Antifungal Drugs ◽

Candida Auris ◽

Healthcare Facilities ◽

Environmental Surfaces ◽

Route Of Transmission ◽

Indirect Exposure ◽

Ultraviolet C ◽

Severe Infections ◽

Uv C

Background:Candida auris is an emerging fungal pathogen that is often resistant to major classes of antifungal drugs. It is considered a serious global health threat because it has caused severe infections with frequent mortality in over a dozen countries. C. auris can survive on healthcare environmental surfaces for at least 7 days, and it causes outbreaks in healthcare facilities. C. auris has an environmental route of transmission. Thus, infection prevention strategies, such as surface disinfection and room decontamination technologies (eg, ultraviolet [UV-C] light), will be essential to controlling transmission. Unfortunately, data are limited regarding the activity of UV-C to inactivate this pathogen. In this study, a UV-C device was evaluated for its antimicrobial activity against C. auris and C. albicans. Methods: We tested the antifungal activity of a single UV-C device using the vegetative bacteria cycle, which delivers a reflected dose of 12,000 µW/cm2. This testing was performed using Formica sheets (7.6 × 7.6 cm; 3 × 3 inches). The carriers were inoculated with C. auris or C. albicans and placed horizontal on the surface or vertical (ie, perpendicular) to the vertical UV-C lamp and at a distance from 1. 2 m (~4 ft) to 2.4 m (~8 ft). Results: Direct UV-C, with or without FCS (log10 reduction 4.57 and 4.45, respectively), exhibited a higher log10 reduction than indirect UV-C for C. auris (log10 reduction 2.41 and 1.96, respectively), which was statistically significant (Fig. 1 and Table 1). For C. albicans, although direct UV-C had a higher log10 reduction (log10 reduction with and without FCS, 5.26 and 5.07, respectively) compared to indirect exposure (log10 reduction with and without FCS, 3.96 and 3.56, respectively), this difference was not statistically significant. The vertical UV had statistically higher log10 reductions than horizontal UV against C. auris and C. albicans with FCS and without FCS. For example, for C. auris with FCS the log10 reduction for vertical surfaces was 4.92 (95% CI 3.79, 6.04) and for horizontal surfaces the log10 reduction was 2.87 (95% CI, 2.36–3.38). Conclusions:C. auris can be inactivated on environmental surfaces by UV-C as long as factors that affect inactivation are optimized (eg, exposure time). These data and other published UV-C data should be used in developing cycle parameters that prevent contaminated surfaces from being a source of acquisition by staff or patients of this globally emerging pathogen.Funding: NoneDisclosures: None

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