A recent study led by Yoram Gerchman discovered that a strain of human coronavirus (HCoV-43) is sensitive to UVC light (UV light at levels of 200nm to 280nm), indicating that it can probably be used in killing the virus that causes the disease COVID-19. The researchers found that certain wavelengths of LED light, such as 285 nm or 265 nm, are effective in “inactivating 99.9% of the coronavirus in under 30 seconds” (MedicalNewsToday). Based on these findings, public health experts are suggesting that UVC lights can be used as disinfectants in public and private areas.
However, there's a bit of a problem.
UVC lights can cause damage to the skin and eyes and can eventually lead to cancer, which is similar to the harmful effects of sunlight, ultraviolet rays. If the lights are used properly in unoccupied areas, they could prove as a useful COVID-19 disinfectant. To clear any misconceptions, the lights cannot be used to inactivate the virus in patients that are already infected, as exposing COVID-19 patients to ultraviolet rays would be extremely risky and unsafe.
It should be re-emphasized that the study used HCoV-43 for experimentation, and researchers have not yet studied the influence of UVC lights on SARS-CoV-2. SARS-CoV-2 is the virus that causes the disease COVID-19 in patients, whereas HCoV-43 is a strain of coronavirus that causes less severe symptoms in patients. At the time of the study, the researchers would have needed a more secure lab to study the virus that causes COVID-19, and the lab available to them was able to research the less severe virus, HCoV-43. Despite using a different virus, experts believe that the findings are still applicable to SARS-CoV-2, and the only difference may be the duration of UVC light exposure needed to fully inactivate the virus.
Using this research, public areas such as hospitals have been using UVC light to clean unoccupied spaces. Researchers also think that the lights can be used in air conditioning systems to disinfect the air and limit the spread of COVID-19. Besides COVID, Gerchman believes that “UV in general and UV-LEDs are effective in combating pathogens”, and as the world discovers new viruses “UV is and will take part in battling such."