In 2017, CADTH’s horizon scanning service reviewed a portable pulsed-xenon ultraviolet (UV) light system, a then-emerging technology to supplement existing cleaning and disinfection processes in hospital rooms.1 Since then, robotic UV light disinfection systems have been subject to health technology assessment2 and automated devices that use hydrogen peroxide vapour (vaporous hydrogen peroxide [VHP]) to disinfect surfaces have emerged.3 In light of the COVID-19 pandemic, questions about the potential role of robotic disinfection systems in this context have been raised.4
How it Works
A supplement to existing manual cleaning and disinfection practices, robotic disinfection systems are automated portable devices intended for use in unoccupied rooms to reduce health care acquired infections (HAIs).2,3,5 Following placement and set-up by a trained operator, the devices are activated (on delay or remotely) and automatically complete a treatment cycle before being repositioned (to ensure complete room coverage) or removed. 2,3,5 This article discusses two approaches to robotic disinfection in health care settings: UV germicidal irradiation (UVGI) or VHP also called hydrogen peroxide fogging.
Ultraviolet Germicidal Irradiation
UVGI robots work by emitting UV-C light (200 nm to 280 nm wavelength) or UV-B (280 nm to 320 nm). The light emitted by the robots destroys DNA in bacteria, viruses, and other harmful microorganisms preventing their ability to replicate and infect humans.2,5 There are two type of UVGI robots, those that disinfect using continuous UV-C light produced by mercury bulbs and those that disinfect using pulses of UV-C and UV-B light produced by xenon bulbs.2,5 The duration of a treatment cycle varies by device, typically between 10 and 45 minutes.2,5 Depending on the device, set-up and positioning may also vary.2,5 Some devices use a single robot in a single location for the entire treatment cycle, while others use multiple devices placed around the room or a single device that is moved periodically to ensure coverage.2,5
Hydrogen Peroxide Vapour
VHP robots generally work by releasing one of two forms of vapour into a sealed room until it covers all surfaces, killing bacteria, viruses, and other microorganisms.3 Condensed hydrogen peroxide (or “wet”) systems heat 30% to 35% hydrogen peroxide until it becomes a vapour.3 Aerosolization (or “dry mist” or “dry gas”) systems use pressurization or nebulization to distribute 6% hydrogen peroxide throughout the enclosed space.3 The devices are usually activated from outside the room and VHP sensors are used to detect any leakage and ensure VHP has decreased to a safe level before people re-enter the room.3 In a case study of one VHP robot, the reported treatment time for one VHP device was two hours.6
Who Might Benefit?
In Canada, 8,000 people die from HAIs and another 220,000 are infected each year.7 Infections caused by organisms such as Clostridium difficile (C. difficile), methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) are of particular concern in Canadian health care settings7 and their prevention is the focus of much of the research into using robotic UVGI and VHP robots to supplement disinfection practices.2,8,9 COVID-19 may also be transmitted in health care facilities putting patients, health care workers, and the public at risk.10 The current understanding of COVID-19 indicates that the disease may spread through contaminated surfaces.11
Availability in Canada
In Canada, UVGI disinfection systems do not require a medical device licence from Health Canada, but the manufacturer must ensure that their products comply with the Radiation Emitting Devices Act and Radiation Emitting Devices Regulations.1 Information regarding the regulation of VHP disinfection systems in Canada was not identified. Several devices are currently available in Canada. These include, but are not limited to:
- Pulsed-xenon UV light systems
- Lightstrike Germ-Zapping Robot (Xenex Disinfection Systems, San Antonio, TX).12
- Continuous UV-C light systems
- UVD Robot (UVD Robots, Odense, Denmark)13
- Tru-D SmartUVC (Tru-D SmartUVC, Memphis, TN).14
- VHP systems
- Bioquell BQ-50 (PharmaMedSci, St. Laurent, QC)15
- Bioquell BQ-EMS (PharmaMedSci, St. Laurent, QC)15
- Nocospray Disinfection System (AMG Medical Inc., Montreal)16
- VHP Victory Biodecontamination Unit (STERIS, Mentor, Ohio).17
What Does it Cost?
The costs of implementing UVGI robots were estimated by Ontario Health (Quality) (then, Health Quality Ontario) in a 2018 health technology assessment.2 The authors estimated costs to owning pulsed-xenon and continuous UV-C robots as:
- Pulsed-xenon UV light systems
- Purchase price, CA$142,325 (four-year warranty).
- Continuous UV-C light systems
- Purchase price, CA$124,517 (one-year warranty)
- Leasing price, CA$53,424.
Warranty costs covering replacement bulbs, parts, and technical support ranged from CA$11,500 to C$13,356 annually. Other operating costs estimated in the report included CA$60,000 per year for a device operator. The authors also conducted a budget impact analysis concluding the five-year costs of owning two devices to be CA$586,023 for pulsed-xenon robots and CA$634,255 for continuous UV-C robots in Ontario hospitals.
Two conference abstracts estimated the costs of implementing UVGI systems technologies in Canadian settings.18,19 The authors concluded that UVGI systems may deliver value for money18 and may save money by reducing HAIs.19
No information about the costs of implementing VHP robots was identified.
Best practices for environmental cleaning and disinfection of health care environments involve the physical removal of visible and invisible material such as dirt, blood, and microorganisms (cleaning) and killing disease-causing microorganisms (disinfection).20 Cleaning and disinfecting complex health care environments requires careful selection of equipment and materials, establishing practices for hand hygiene, and use of personal protective equipment.20
In the context of COVID-19, WHO recommends cleaning and disinfection practices that clearly delineate roles for staff, pay particular attention to high-touch services, and help health care workers avoid contaminating hands and equipment during patient care.21 The organization also recommends the careful selection of disinfectants to ensure they are appropriate for clinically relevant pathogens in addition to SARS-CoV-2.21
What is the Evidence?
Our literature search focused on publications about robotic disinfection systems published after CADTH’s 2017 horizon scan.1
Ultraviolet Germicidal Irradiation
UVGI robots were evaluated in a 2018 health technology assessment by Ontario Health (Quality).2 The report assessed the available evidence for pulsed xenon- and mercury-based devices to prevent HAIs. The authors were “unable to make a firm conclusion about the effectiveness of this technology on [hospital-acquired infections] given the very low to low quality of evidence.” In 2019, a CADTH rapid review of the clinical effectiveness and guidelines of UVGI robots made similar conclusions.22
A 2020 evaluation of UVGI robots by ECRI found limited evidence that the devices reduce HAIs.5
A 2019 systematic review and meta-analysis examined the effectiveness of pulsed-xenon UV light systems to reduce HAIs.8 The authors concluded that, based on evidence from before-and-after studies, the devices may help reduce some HAIs (i.e., C. difficile infections and MRSA) but not VRE.8 In a 2018 systematic review and meta-analysis on the effectiveness of UVGI and VHP to reduce multi-drug resistant HAIs the authors concluded that UVGI may help reduce infections caused by C. difficile and VRE, but not MRSA infections.9
Vaporous Hydrogen Peroxide
In a 2020 assessment of the clinical effectiveness of VHP robots for reducing health care acquired infection,3 ECRI found inconclusive evidence and a need for further study of the technology based on the findings of one systematic review and meta-analysis9 of low-quality studies.
Disinfection Robots and COVID-19
Reports and studies of UVGI to prevent the spread of COVID-19 appear to be limited. In guidance from ECRI on the role of UVGI to prevent the spread of COVID-19, the authors note that the SARS-CoV-2 virus is expected to be susceptible to UV light.4 Recommendations for improved patient safety in operating rooms suggests that higher-risk locations (e.g., anesthesia work areas) in “at-risk” rooms be treated with UV-C to reduce the risk of perioperative infections, including COVID-19.23 A retrospective multi-centre study of infection control precautions to prevent the spread of COVID-19 in endoscopy centres in China reported widespread use of UV light disinfection, but did not evaluate its effectiveness.24
No reports or studies using VHP to prevent the spread of COVID-19 were identified.
Exposure of patients, staff, and visitors to UV-C radiation produced by UVGI robots is the primary safety concern related to their use.5 Safety precautions such as motion sensors to stop treatment cycles and signage to deter entry into spaces being cleaned by UVGI robots are typically used.5 Blackout curtains may also be used to prevent UV light from escaping spaces being treated.1
Similarly, exposure to VHP appears to be the primary safety concern when using these devices.3 When treating a room with VHP, the space is hermetically sealed to prevent leakage and sensors are used to detect leakage and determine when it is safe to re-enter the room.3
Issues to Consider
Using UVGI robots to supplement existing cleaning and disinfection practices requires training staff and changes to existing workflows to accommodate the added time needed for appropriate use.1,2,5,8 The need for empty rooms may not be practical in hospitals with multi-patient rooms.2,8 Similar issues may need to be considered should UVGI be used in the context of COVID-19.4
Direct exposure to UV light is necessary for UVGI robots to be effective. Incomplete cleaning that leaves visible dirt, shadows caused by improper placement of the device, closed doors, and the like may all impact the robot’s ability to disinfect contaminated areas.5 UV light can damage and degrade materials, such as plastics, over time.5 It may be necessary to remove or protect important equipment before treating a room with UVGI.5
No literature discussing the implementation of VHP robots was identified.
A limitation of UVGI and VHP robots is that rooms need to be empty so that they can be used. Technologies that continuously disinfect the air or surfaces in health care environments while rooms are occupied are emerging or in development.25-39
One approach to continuous disinfection forces air to pass through a UV light filter installed in the ventilation system before it enters the room.25-35 A similar approach has also been proposed to disinfect the air in ambulances.36 Using UV-A lighting fixtures to continuously disinfect surfaces has also been proposed.37 Another approach uses diluted hydrogen peroxide produced from air in concentrations below human safety thresholds to continuously disinfect health care environments while they are in use.38,39
The role of automated disinfection systems in preventing HAIs and COVID-19 is unclear. There is a need for more research comparing automated devices,5 and evaluating their clinical and cost-effectiveness for preventing HAIs.9
1. Mason J. A pulsed-xenon UV light disinfection system for hospital rooms. CADTH Health Technology Update. 2017(19):8-10. https://www.cadth.ca/sites/default/files/pdf/Health_Technology_Update_Issue_19.pdf. Accessed 2020 Aug 31.
2. Health Quality Ontario. Portable ultraviolet light surface-disinfecting devices for prevention of hospital-acquired infections: a health technology assessment. Ont Health Technol Assess Ser. 2018;18(1):1-73.
3. Hydrogen peroxide room disinfection for preventing healthcare-associated infections. Plymouth Meeting (PA): ECRI Institute; 2020: www.ecri.org. Accessed 2020 Jul 15.
4. Using UV disinfection safely and effectively: technology challenges during the COVID-19 pandemic. Plymouth Meeting (PA): ECRI Institute; 2020: www.ecri.org. Accessed 2020 Jul 15.
5. Evaluation background: UV room disinfection devices. Plymouth Meeting (PA): ECRI Institute; 2020: www.ecri.org. Accessed 2020 Jul 15.
6. Case study COVID-19: Eliminating the pathogen from surfaces is extremely important. St. Paul (MN): Ecolab USA Inc.; 2020: https://www.bioquell.com/wp-content/uploads/2020/04/Bioquell-Biodecontamnation-Case-Study-COVID-19-HC001-MKT-196.pdf. Accessed 2020 Apr 16.
7. Canadian Patient Safety Institute. Healthcare associated infections (HAI). 2020: https://www.patientsafetyinstitute.ca/en/Topic/Pages/Healthcare-Associated-Infections-(HAI).aspx. Accessed 2020 Aug 11.
8. Dong Z, Zhou N, Liu G, Zhao L. Role of pulsed-xenon ultraviolet light in reducing healthcare-associated infections: a systematic review and meta-analysis. Epidemiol Infect. 2020;148:e165.
9. Marra AR, Schweizer ML, Edmond MB. No-touch disinfection methods to decrease multidrug-resistant organism infections: a systematic review and meta-analysis. Infect Control Hosp Epidemiol. 2018;39(1):20-31.
10. Government of Canada. COVID-19 pandemic guidance for the health care sector. 2020; https://www.canada.ca/en/public-health/services/diseases/2019-novel-coronavirus-infection/health-professionals/covid-19-pandemic-guidance-health-care-sector.html. Accessed 2020 Aug 15.
11. Government of Canada. Coronavirus disease (COVID-19): prevention and risks. 2020; https://www.canada.ca/en/public-health/services/diseases/2019-novel-coronavirus-infection/prevention-risks.html. Accessed 2020 Aug 13.
12. Xenex Disinfection Systems. LightStrike Germ-Zapping Robots. 2020; https://www.xenex.com/our-solution/lightstrike. Accessed 2020 Aug 10.
13. UVD Robots. Home - UVD Robots. 2020; http://www.uvd-robots.com. Accessed 2020 Jul 30.
14. Tru-D SmartUVC. UV Light Disinfection: Tru-D. 2020; https://tru-d.com. Accessed 2020 Aug 10.
15. PharmaMedSci. Bioquell. 2020; https://www.pharmamedsci.com/bioquell-medical. Accessed 2020 Aug 10.
16. AMG Medical Inc. Nocospray disinfection system. 2020; http://www.nocospray.ca/en/product/nocospray-disinfection-system. Accessed 2020 Aug 10.
17. STERIS. VHP VICTORY biodecontamination unit. 2020; https://www.sterislifesciences.com/products/equipment/vhp-sterilization-and-biodecontamination/vhp-victory-biodecontamination-unit. Accessed 2020 Aug 10.
18. Hall W. Cost effectiveness of ultra-violet germicidal irradiation in Canadian health region. Value Health. 2018;21(Suppl 1):S167.
19. Hall W. PIN88 Interrupted time series analysis of UVGI technology to reduce infection rates in a Canadian health region - an economic analysis. Value Health. 2019;22(Suppl 2):S209.
20. Best practices for environmental cleaning for prevention and control of infections in all health care settings. Toronto (ON): Ontario Agency for Health Protection and Promotion (Public Health Ontario); 2018: https://www.publichealthontario.ca/-/media/documents/B/2018/bp-environmental-cleaning.pdf?la=en Accessed 2020 Jul 24.
21. Cleaning and disinfection of environmental surfaces in the context of COVID-19. Geneva (CH): World Health Organization (WHO); 2020: https://apps.who.int/iris/bitstream/handle/10665/332096/WHO-2019-nCoV-Disinfection-2020.1-eng.pdf. Accessed 2020 Jul 24.
22. Non-manual ultraviolet light disinfection for hospital acquired infections: a review of clinical effectiveness and guidelines. (CADTH Rapid response report: summary with critical appraisal). Ottawa (ON): CADTH; 2019: https://www.cadth.ca/sites/default/files/pdf/htis/2019/RC1091%20Non-Manual%20UV%20Light%20Disinfection%20Final.pdf Accessed 2020 Aug 31.
23. Dexter F, Parra MC, Brown JR, Loftus RW. Perioperative COVID-19 defense: an evidence-based approach for optimization of infection control and operating room management. Anesth Analg. 2020;131(1):37-42.
24. Huang Q, Liu G, Wang J, et al. Control measures to prevent Coronavirus disease 2019 (COVID-19) pandemic in endoscopy centers: a multi-centre study. Dig Endosc. 2020 May 30.
25. Anis HK, Curtis GL, Klika AK, et al. In-room ultraviolet air filtration units reduce airborne particles during total joint arthroplasty. J Orthop Res. 2020;38(2):431-437.
26. Nunayon SS, Zhang HH, Lai ACK. A novel upper-room UVC-LED irradiation system for disinfection of indoor bioaerosols under different operating and airflow conditions. J Hazard Mater. 2020;396:122715.
27. Nunayon SS, Zhang H, Lai ACK. Comparison of disinfection performance of UVC-LED and conventional upper-room UVGI systems. Indoor Air. 2020;30(1):180-191.
28. Hakim H, Gilliam C, Tang L, Xu J, Lee LD. Effect of a shielded continuous ultraviolet-C air disinfection device on reduction of air and surface microbial contamination in a pediatric oncology outpatient care unit. Am J Infect Control. 2019;47(10):1248-1254.
29. Cook TM, Piatt CJ, Barnes S, Edmiston CE Jr. The impact of supplemental intraoperative air decontamination on the outcome of total joint arthroplasty: a pilot analysis. J Arthroplasty. 2019;34(3):549-553.
30. Bischoff W, Russell G, Willard E, Stehle J Jr. Impact of a novel mobile high-efficiency particulate air-ultraviolet air recirculation system on the bacterial air burden during routine care. Am J Infect Control. 2019;47(8):1025-1027.
31. Yang Y, Zhang H, Nunayon SS, Chan V, Lai ACK. Disinfection efficacy of ultraviolet germicidal irradiation on airborne bacteria in ventilation ducts. Indoor Air. 2018;28(6):806-817.
32. Heredia-Rodriguez M, Alvarez-Fuente E, Bustamante-Munguira J, et al. Impact of an ultraviolet air sterilizer on cardiac surgery patients, a randomized clinical trial. Med Clin (Barc). 2018;151(8):299-307.
33. Guimera D, Trzil J, Joyner J, Hysmith ND. Effectiveness of a shielded ultraviolet C air disinfection system in an inpatient pharmacy of a tertiary care children's hospital. Am J Infect Control. 2018;46(2):223-225.
34. Ethington T, Newsome S, Waugh J, Lee LD. Cleaning the air with ultraviolet germicidal irradiation lessened contact infections in a long-term acute care hospital. Am J Infect Control. 2018;46(5):482-486.
35. Curtis GL, Faour M, Jawad M, Klika AK, Barsoum WK, Higuera CA. Reduction of particles in the operating room using ultraviolet air disinfection and recirculation units. J Arthroplasty. 2018;33(7S):S196-S200.
36. Song L, Li W, He J, et al. Development of a pulsed xenon ultraviolet disinfection device for real-time air disinfection in ambulances. J Healthc Eng. 2020;2020:6053065.
37. Livingston SH, Cadnum JL, Benner KJ, Donskey CJ. Efficacy of an ultraviolet-A lighting system for continuous decontamination of health care-associated pathogens on surfaces. Am J Infect Control. 2020;48(3):337-339.
38. Oon A, Reading E, Ferguson JK, Dancer SJ, Mitchell BG. Measuring environmental contamination in critical care using dilute hydrogen peroxide (DHP) technology: an observational cross-over study. Infect Dis Health. 2020;25(2):107-112.
39. Rutala WA, Kanamori H, Gergen MF, et al. Evaluation of dilute hydrogen peroxide technology for continuous room decontamination of multidrug-resistant organisms. Infect Control Hosp Epidemiol. 2019;40(12):1438-1439.