About a decade ago, David Brenner, a professor of radiation biophysics at Columbia University Irving Medical Center in New York, began thinking about the problem of drug-resistant bacteria.
Superbugs are a real concern and a focus of attention for the pharmaceutical industry, but Brenner, as a physicist, wondered if there could be something he could do: He thought about ultraviolet light. In doing so, you started a path that has placed you on the front lines of COVID-19.
For more than a century, we have known that ultraviolet light kills microbes, and germicidal ultraviolet light, with a wavelength of 254 nanometers (nm), has been used increasingly in recent decades to sterilize operating rooms, shelters for the homeless and other spaces. But germicidal ultraviolet light can be harmful to humans, particularly the eyes and skin, so its use is limited to spaces where humans will not be directly exposed. Brenner began to wonder if there was a type of UV light that could kill microbes but was still safe for humans exposed to it.
In principle, there was: Ultraviolet light at a wavelength of 222 nm (what many call “far UVC”) cannot penetrate the eyes and skin.
Brenner has spent years since then trying to push the science to turn information into application. (He has also given two TED talks on the subject.) Although he initially focused on drug-resistant bacteria, he and his colleagues began thinking a few years ago about powerful UVC and its potential to safely decontaminate the air and prevent transmission. of substances in the air. viruses such as influenza. His studies showed that it worked: light could effectively kill the influenza virus by spraying it into the air, in an environment similar to a public space.
When Brenner learned of a new coronavirus outbreak earlier this year, he and his team quickly organized a study to test whether 222nm light would efficiently kill aerosolized human coronaviruses, incapable of contracting SARS-CoV-2 in En. At that time, they used types that are commonly circulating and can cause the common cold, just like they did with the flu. It did, indicating that when continuously applied at the current regulatory exposure limit, far UVC inactivates approximately 90% of airborne viruses in eight minutes and 99.9% in approximately 16 minutes. They are currently conducting the same study with aerosolized SARS-CoV-2.
Beyond awareness, there are other issues that slow the adoption of far UVC. While Nardell and his colleagues are fairly confident that human exposure is safe (a couple, including an expert on the effects of ultraviolet rays on the eyes, have been exposing themselves to 222 nm light), he admits that ” safety studies are not yet available.
The Dundee lab plans to repeat the study with many more subjects and a well-filtered lamp as soon as they get funding for it, Nardell says.
Brenner, who highlights the importance of establishing safety data, says that his laboratory and others in the US and other countries have conducted many studies demonstrating safety in a variety of systems, primarily studying human skin and eyes and the skin in mice. His lab is about to complete a 60-week study in which they have exposed 100 hairless mice to 222 nm of light, The mice are regularly tested for general health and eye and skin problems, but so far they haven’t shown any.
