Autonomous Disinfecting Robots Join the Front Lines of the Coronavirus Battle

By Per Juul Nielsen, CEO, UVD Robots

As the global war against the coronavirus rages on, interest in safe, disinfecting technology that can kill the virus in hospitals is growing. Next-generation disinfecting robots created a few years ago for the purpose of disinfecting hospital rooms using UV-C light have been gaining significant attention as a way to disinfect against Coronavirus. In particular, the technology is enabling hospitals to protect patients, medical professionals and front-line cleaning staff from infection while simultaneously bringing greater operational efficiency.

Using UV light is not a new idea. Since the 1870s it was known that ultraviolet light had an inhibiting effect on bacteria, and history shows that in 1895, Niels Ryberg Finsen used concentrated beams of ultraviolet light to treat patients with lupus vulgaris with some success. UV-C was also used to disinfect the municipal water supply of Marseille, France, in 1908, and Westinghouse developed the first commercial UV-C germicidal lamps during the 1930s to be used primarily in hospitals. After World War II, UV-C was used for sterilizing air in hospitals, kitchens, meat storage and processing plants, bakeries, breweries, dairies, beverage production, pharmaceutical plants and animal labs. It became a major component in the control and eradication of tuberculosis, but the advent of antibiotics and vaccines meant that the technology was largely abandoned for decades.

The Renaissance of UV-C Light

Today, with the emergence of antibiotic-resistant bacteria and viruses that we cannot vaccinate against, this technology is seeing a renaissance as scientific reports continue to underscore the benefits and importance of UV-C light in disinfecting. One study from September of 2019 evaluating the effectiveness of improved cleaning interventions in hospitals reported that approximately 5–30% of surfaces remain potentially contaminated due to the inability of existing detergent formulations and disinfectants to kill certain kinds of bacteria.

In recent years, hospitals have been using UV-C light to sanitize rooms to reduce Hospital Acquired Infections (HAIs) and using a cluster of UV-C emitting lamps that can be wheeled into a room and disinfected in an hour or less, reaching surfaces that may be overlooked by cleaning staff. However, the drawback is that this early technology requires a human to enter the room (between cycles) and move the UVC-emitting lamp from one position to another, so all surfaces, in theory, receive the maximum dosage of radiation. This calls into question effectiveness, and the possibility for some surfaces either “shadowed,” or further from the lamp, could potentially remain infected.

The Shadow Effect

To understand the shadow effect, one need only look as far as the Sun, by far the Earth’s most powerful source of UV-C radiation. The amount of UV-C generated by the Sun every second is higher than all of the artificially generated UV-C in the history of UV-C disinfection combined. We all know that overexposure to the Sun’s UV light can result in a sunburn. However, this is impossible at night, when the Earth blocks the light from the part of the planet facing away from the Sun.

Similar to shadows, another law of light that complicates the use of UV-C as a room disinfectant is intensity over distance, which can be easily calculated using the inverse square law. The inverse square law dictates that to reach the same level of UV-C intensity (or germicidal effect) achieved at 1m distance, it is necessary to radiate for 9 times longer from 3m distance and 16 times longer from 4m distance. UV-C intensity at 1m is 100% therefore, the light intensity at 2m will fall to 25% (a quarter). At 3m the intensity drops further to 11% (a ninth) and at 4m, intensity is only 6.25%.

When applying the idea of shadows and distance to a hospital room scenario, you can apply this thinking to the effectiveness of UV-C light. In fact, according to Professor Valerie Edwards-Jones of Manchester Metropolitan University who explored the effectiveness of UV-C light in the killing of Coronavirus in her report, “UV-C Light and Coronavirus Statement,” she explained that “shadowing effects” could reduce the UV-C intensity, coupled with distance from the contaminated surfaces can vary enormously. 

 99.99 Percent Disinfection Rate

Unlike their stationary counterparts that cannot reach shadowed areas or move close to all surfaces in a room, a self-driving robot has the ability to autonomously reposition itself multiple times and to disinfect during repositioning - critical factors in achieving the highest possible level of disinfection to eliminate bacteria and other harmful microorganisms.

 Hospitals around the globe are benefiting from reduced shadowing and consistent exposure to every section of a room resulting in a 99.99% disinfection rate, including coronavirus.

 Further, a major advantage of using robotic technology over manual disinfection systems is traceability, as the robot will repeat the validated room disinfection precisely time and time again. If it does not, it will deliver a fail report, producing a much higher level of accountability than stationary lights.

The development of autonomous disinfecting robots started in 2014, when a group of Danish hospitals demanded a more effective way of reducing infection rates in hospitals. Through a collaboration between bacteriologists, virologists and hospital staff from hospitals, and robot developers, designers, engineers, investors and business people from Blue Ocean Robotics, UVD Robots deployed its first autonomous robot at the Odense University Hospital in Denmark in 2018.

These self-driving robots are now able to disinfect a hospital room typically in about 10-15 minutes. UV-C light is also known to kill airborne microbes, which is becoming increasingly of interest. UV-C light is not harmful to humans in small dosages, and the light emitted through door cracks, etc. is not a health concern.

Further, UV-light disinfection system also does not require changes in a room’s ventilation, and does not leave residue after treatment. Damage to materials in the room was not reported during the use of UV-light disinfection systems.

A large volume of UVD Robots are currently in operation in close to 50 countries worldwide, and have now been deployed at hospitals in areas hard hit by the coronavirus such as Wuhan in China and in Italy.

Operational Efficiency

In American hospitals alone, the Centers for Disease Control (CDC) estimates that HAIs account for an estimated 1.7 million infections and 99,000 associated deaths each year. Further, according to research, patients who acquire infections from surgery spend, on average, an additional 6.5 days in the hospital, are five times more likely to be readmitted after discharge and twice as likely to die. Moreover, surgical patients who develop infections are 60 percent more likely to require admission to a hospital's intensive care unit. Surgical infections are believed to account for up to ten billion dollars annually in healthcare expenditures.

For some perspective on how autonomous disinfecting robots can help, last December, just before the coronavirus outbreak, an autonomous robot was able to disinfect an entire hospital theatre suite of 17 rooms including corridors. The disinfection was comprised of 60 separate disinfection positions, and was completed in under 2 hours and involved less than 10 minutes of manual labor, underscoring how state-of-the-art robotic technology can drastically increase the coverage of automated infection prevention procedures within a theatre setting. For the first time in history, theatre personnel are able to routinely disinfect between procedures, as well as carry out a daily yet thorough disinfection of the complete theatre suite, in under 2 hours using minimal labor resources. This drastically reduced associated labor costs without sacrificing efficiency.

Beyond the Pandemic

As we move beyond the coronavirus pandemic, it’s likely that we as a global society will emerge with a very different sense of the need for disinfection, and will demand for greater protection against not only hospital grade infections, but new infectious risks to health in other environments.

While the coronavirus is pulling the effectiveness of UV-C light into the spotlight, self-driving disinfecting robots were already being successfully deployed to fight HAIs well before. Looking ahead, prevention will likely become central to controlling and eliminating the spread of diseases like coronavirus, and we will see this disinfecting technology moving back into environments similar to those where UV-C light was being utilized in the 19th century and more, including factories, food storage, prisons, schools, supermarkets, airports and more.