It is well established in infection prevention practice that surfaces in hospital rooms are continually contaminated by infectious pathogens. The sources of these dangerous pathogens range from people who enter the room with contaminated hands and compromised clothing, from contaminated instruments and items that are brought in and out of the room like personal and enterprise issued mobile devices, and from the patient themselves. In addition, the air entering the room is not sterile and deposits pathogen containing fomites which settle onto all the surfaces adding to the degree of bio burden compromise.
It is also well established that the accumulated pathogens residing on high touch surfaces are then transferred onto bare or gloved hands and clothing of nurses, doctors, visitors, and environmental workers when touched, which in turn puts patients at great risk since they or their immediate surroundings are consequently contaminated by touch transfer mechanisms. Hence, even perfect attention to between patient visit hand sanitation by healthcare workers (HCWs); 100% compliance, and effective sanitization of hands to – 4 log10 inactivation, (99.99%); which is not currently achieved), will leave the hands contaminated while performing tasks within the room. This situation is judged to be unavoidable.
Accordingly, the ultimate solution espoused by WHO is hand sanitation immediately prior to patient contact; the Five Special Moments (‘FSM’), so that patients or the patient’s surroundings are not contaminated as a result of attention or care from a healthcare worker, attendant, or a visitor. Currently, the use of alcohol rubs just prior to contact is recommended by WHO for hand sanitation despite the fact that during a shift 100 or more alcohol rub hand sanitations, each taking at least 30 seconds, almost one hour dedicated to hand sanitation per shift, would be required. Moreover alcohol rub is not free of hand irritation and is totally ineffective on spores such as C. diff and some viruses. Hand washing is usually less effective, takes more time and is generally more irritating. There is no currently available product that can meet the WHO FSM requirement so it remains an objective, but not yet a reality.
As a response to problematic hand hygiene, a number of companies are now offering UV-C-based, room disinfection devices which have as their purpose to supplement terminal cleaning. They nominally sanitize room surfaces in as little as 15 minutes, and by lowering bio burden levels, help to minimize additional contamination of hands and clothing when the surfaces are contacted later. This sanitation process must be carried out in a vacant room due to the dangers UV-C poses to unprotected eyes, so it is generally performed only after patient discharge and cleaning by environmental workers.
To understand the efficacy of this approach, it is important to recognize that to inactivate pathogens, especially hardy C. difficile endospores, to the nominal – 4 log10 or 99.99% sanitation level in 15 minutes, typically requires a direct, continuous, line of sight UV-C dose for the entire 900 second period on the entire surface area. Keeping in mind that UV-C intensity of a source falls off with dramatically with distance from that source. This approach could be effective in sanitizing most of a room’s surfaces from normal incidence rays falling directly on these surfaces. This would be the case for walls, which are actually not touch surfaces in most cases.