Advancing from traditional chemical disinfecting agents, UV-C light has emerged as a proven method to effectively destroy pathogens, rendering them inactive and reducing the risk of Hospital-Acquired Infections (HAIs) in healthcare settings where pathogen proliferation is high.
However, factors like location, shadowing, and surface topography can impact UV-C light’s effectiveness. As a result, healthcare facilities face the challenge of verifying the real-world efficacy of their UV-C light systems. Validation is therefore crucial to ensure thorough and successful decontamination and disinfection.
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How UV-C Light Kills Pathogens and Prevents Infections in Healthcare
To better understand the efficacy and challenges of UV-C light, The Journal of Hospital Infection detailed how it disrupts pathogens in healthcare facilities. UV-C light damages the DNA and RNA of pathogens by breaking their molecular structure. This prevents pathogens from replicating, effectively rendering them inactive.
Whilst UV-C light is proven to be an effective method for deactivating pathogens, its ability to disrupt a pathogen’s DNA or RNA depends on the intensity of exposure. Insufficient exposure may not achieve complete inactivation, leaving some pathogens unaffected. Therefore, ensuring that pathogens receive a sufficient UV-C dose is crucial for effective decontamination.
Challenges of UV-C Light: Space, Shadowing, and Surface Barriers in Hospitals
Aside from setting the proper dose, several factors can affect UV-C light’s inactivation of pathogens. A study on the Impact of Room Location on UV-C Irradiance outlines several distance-related variables that affect real-world efficacy. Using radiometric UV-C light sensors in an ICU room and a surgical ward, it was found that UV-C irradiance is strongest on surfaces directly exposed or closer to the UV-C light source, while shaded or distant surfaces receive significantly lower doses. The study finds that UV-C light’s efficacy is relative to the surface location and orientation within the room.
Ultimately, UV-C light’s effectiveness is limited by its direct reach. When objects obstruct its path, shadowing occurs, meaning that areas blocked from the light may not be fully disinfected, leaving active pathogens behind. Additionally, uneven or rough surfaces can create more shadows, serving as an additional challenge to UV-C light decontamination and disinfection.
Why Validating UV-C Light Decontamination is Essential for Healthcare Safety
Simply using UV-C light is not enough. Besides confirming the correct dosage, optimal device placement, and accounting for room topography, validating each UV-C light cycle is a necessary step to ensure that each decontamination cycle achieves its full effectiveness.
Research on the Effectiveness of UV-C Light Devices has shown that not all devices perform equally. Hence, evaluating an actual decontamination cycle is essential to verifying device performance. The study introduced a ‘do-it-yourself’ test protocol where commercial Bacillus atrophaeus spores, a resilient form of bacterium, are used to determine whether the devices are able to deliver a minimum of log-3 reduction of pathogens. A log-3 kill indicates the elimination of 99.9% of pathogens. Another study on Ultraviolet-C (UV-C) monitoring proposed using commercial colorimetrics as a basic measure for checking the amount of UV-C light delivered to hospital rooms, offering a simple form of validation.
Other advanced UV-C systems offer real-time monitoring technologies that allow operators to identify areas receiving insufficient coverage and reposition units accordingly. These systems generate automated validation reports after each cycle, creating an audit trail confirming appropriate UV-C dosage application throughout the treatment area. Such advanced validation approaches enhance UV-C decontamination by improving coverage and ensuring optimal exposure.
The Path Forward:
Implementing Effective Validation Protocols in Healthcare Facilities
The evidence supporting UV-C light against pathogens must be paired with rigorous validation methodologies. Healthcare facilities should implement validation protocols that address their unique environmental challenges through baseline measurements, regular efficacy testing, and quantifiable documentation. Aside from colorimetric indicators and biological testing, choosing a UV-C device that provides active monitoring and validated assurance transforms UV-C technology from a promising innovation into a reliable infection prevention cornerstone. Only through this commitment to validation can we fully realize UV-C light’s potential to protect patients and staff from healthcare-associated infections.
References:
- Boyce, J. M., Farrel, P. A., Towle, D., Fekieta, R., & Aniskiewicz, M. (2016). Impact of room location on UV-C irradiance and UV-C dosage and antimicrobial effect delivered by a mobile UV-C light device. Infection Control & Hospital Epidemiology, 37(6), 667–672. https://doi.org/10.1017/ice.2016.35
- Cadnum, J. L., Jencson, A. L., & Donskey, C. J. (2017). A do-it-yourself test protocol using commercial Bacillus atrophaeus spores to evaluate the effectiveness of ultraviolet-C light room-decontamination devices. Infection Control & Hospital Epidemiology, 38(3), 371–376. https://doi.org/10.1017/ice.2016.276
- Cadnum, J. L., & Donskey, C. J. (2017). Ultraviolet-C (UV-C) monitoring made simple: Colorimetric indicators to assess delivery of UV-C light by room decontamination devices. Infection Control & Hospital Epidemiology, 38(5), 627–629. https://doi.org/10.1017/ice.2017.21
- Lindahl, C. (2019). Ultraviolet-C (UV-C) monitoring made ridiculously simple: UV-C dose indicators for convenient measurement of UV-C dosing. National Institute of Standards and Technology. https://www.nist.gov/document/panel-iv-lindahl
