Clinical studies on the effectiveness of UVGI
As we have mentioned elsewhere, UVGI is a proven technology in the Americas, so there are a number of USA studies that have demonstrated its effectiveness. But we are pleased to note that studies are also being conducted in the UK.
The importance of bioaerosols in hospital infections and the potential for control using germicidal ultraviolet irradiation
L.A. Fletcher; C.J. Noakes; C.B. Beggs; P.A. Sleigh. Aerobiology Research Group, School of Civil Engineering, University of Leeds
Research at the University of Leeds has looked at the effect of ultraviolet disinfection upon a range of airborne bacterial pathogens. The results have shown that all are susceptible to the effects of UV but the magnitude of the effect is extremely species-dependent. Although history shows that the uptake of UV disinfection has progressed slowly the future looks extremely promising, with increasing concerns over rising numbers of TB outbreaks, new pathogens such as SARS and avian flu and also the increased risk of bioterrorism threats. In addition to clinical applications, this technology would also be similarly applicable to waste management facilities for controlling potential pathogens such as Aspergillus fumigatus. You can read the full paper on the Leeds University site (PDF 
file), and more about related areas of research.
Imperial College study shows UV air disinfection effective against TB
Dr Rod Escombe, of Imperial College London, has recently published the results of his study showing how UV units reduce airborne TB in hospital wards. You can read more details on this page.
USA studies
(Note that the HD-01 units are variously referred to as TRU-D and UVAS in these papers.)
- Alterations of bacteria colony counts in the inanimate environment of an intensive care unit by use of the TRU-D device. Jeffery L. Deal, MD, FACS; Marie Owens, Ph.D. April 15, 2002 To August 1, 2002
This study was designed to test the effectiveness of the TRU-D to deliver doses of UVC in a predictable manner in patient care areas, sufficient to achieve significant reduction of bacteria colony counts in cultures taken from the inanimate environment of an intensive care room. Read the full paper to see how effective bacterial disinfection was proved. (PDF
file) - High-dose ultraviolet C light inactivates spores of Bacillus subtilis var. niger and Bacillus anthracis Sterne on non-reflective surfaces.
Marie U. Owens, David R. Deal, Michael O. Shoemaker, Gregory B. Knudson, Janet E.
Meszaros, Jeffery L. Deal
(published in Applied Biosafety: Journal of the American Biological Safety Association). November 2005.
This investigation showed that spore viability of both B. subtilis var niger as well as B. anthracis Sterne was significantly reduced, reproducibly by 3-5 logs, under extreme contamination levels following dosimetric UV-C exposure. Complete kill can be achieved when the contamination level is lower. You can subscribe to the online journal or read a version of the paper to see how effective bacterial disinfection was proved. (PDF
file). - Comparison of UV C light and chemicals for disinfection
of surfaces in hospital isolation units
B. M. Andersen, MD, PhD; H. Bånrud, DrScient; E. Bøe, BcEcon, MEng; O. Bjordal, MEng; F. Drangsholt, PhD
Published in Infection Control and Hospital Epidemiology July 2006, vol. 27, no. 7
This study was to determine the bactericidal effect on surfaces of ceiling- and wall-mounted UV C (UVC) light in isolation units, compared with standard hospital environmental cleaning and chemical disinfection.
It found that UVC disinfection significantly reduced the number of bacteria on surfaces directly or indirectly exposed to UVC to a very low number. (Completely shadowed areas in the isolation unit (e.g., the bed rail, lockers, and mattresses) still required disinfection by chemicals.) Read the full paper on the University of Chicago Journals web site for details. (PDF
file) -
Disinfection of Acinetobacter baumannii-contaminated surfaces relevant to medical treatment facilities with ultraviolet C light
Vipin K. Rastogi; Lalena Wallace; Lisa S. Smith.
Published in Military Medicine, Volume 172, Number 11, November 2007 , pp. 1166-1169
This study investigated the efficacy of ultraviolet C (UVC) light for decontaminating three hospital-related surfaces, namely aluminium (bed railings), stainless steel (operating tables), and scrubs (laboratory coats). UVC irradiation was found to be very effective in the decontamination of bacteria from all metal surfaces (complete killing). However, it was ineffective in the decontamination of scrubs.
Read the abstract on the Ingenta web site. (Requires payment for full article)
- This page summarises the results of a number of USA studies conducted in a range of hospital facilities to determine the effectiveness of HD-01 decontamination procedures.