The understanding that we can kill bacteria and viruses with sunlight was discovered and researched in the late 19th century. Once we also understood that the airborne transmission of viruses and diseases was a very real concept, the forward-thinking study of Ultraviolet germicidal irradiation and the applications of its use for destroying all harmful pathogens began.
Some of the first studies conducted to discover the potential UVGI has for disinfection took place at Duke University Hospital. Initially, their experiment was to discover the volume of eradication for pathogens in a surgical room, including the supply and instrument tables. What they discovered was that postoperative wound infection rates went down over 10%. From a 11.62% postoperative infection rate without UVGI use to 0.24% with UVGI. With these results, other Duke colleagues and hospitals implemented their own UVGI for operating rooms and were able to replicate similar outcomes.
Studies expanded into testing UV technology at infant wards in other hospitals. Infant’s and Children’s Hospital in Boston set up a controlled experiment to reduce rates for respiratory cross-infections. At the end of the study, the data proved infection rates decreased over 10% with infection rates without UVGI technology being at 12.5% in the control ward and 2.7% infection rates with UVGI. Not only were they able to show UVGI can reduce respiratory cross-infection cases, but also reduced cross-cubicle spread of aerosolized test organisms. Additionally, veteran’s hospitals started to look further into viruses spreading into various wards through the ventilation system. What they were able to conclude was that when using UVGI technology in HVAC systems, the viruses and bacteria that they aerosolized were inactivated prior to reaching other wards, allowing their test rabbits to stay tuberculosis-free.
Costly protocols done in hospitals can be the reactive attempt to contain the airborne transmission of viruses or diseases to other immunocompromised patients or workers. Shutting downwards of hospitals can cost an incredible amount of resources and time. UV-C HVAC installations are designed to work with the air ventilation so that pathogens circulate past the light in the exhaust air duct so it gets disinfected before it is then recirculated or exhausted back into the other rooms of the building. It was in 2005 that the CDC updated its recommendations for UVGI to be used for infection containment in healthcare settings. Four years later they created their first comprehensive guide to using “upper-room UVGI.”
Companies such as Purification LLC have made it their mission to develop and further the field testing of these devices in real-world applications – taking into consideration other factors such as humidity, temperature control, distance of pathogens to the light, and the light frequency measurement.