Can UV light kill the coronavirus?

These uncertain days of the pandemic, many of us are finding, and welcoming, additional ways to protect ourselves and our loved ones from COVID-19. One of the measures we have surely heard about is ultraviolet light (UV), which purportedly kills the virus. 

We shine a light on this theory. Can the UV light in these “sanitizer” gadgets provide another layer of protection to prevent us from being infected? 

According to the International Ultraviolet Association (IUVA), when applied correctly, “UV is a known disinfectant for air, water and surfaces that can help to mitigate the risk of acquiring an infection in contact with the COVID-19 virus…” On the group’s “Fact Sheet on UV Disinfection for COVID-19,” it shares that UV light has been utilized for more than four decades to disinfect drinking water and surfaces, among others, against a whole suite of human pathogens.” The association further reports that all the bacteria and viruses they have tested to date have responded to UV disinfection, noting that some organisms are more susceptible to disinfection through UV than others. 

There are two types of UV light, explains's Amanda Capritto in the article "Using UV light to kill coronavirus: The benefits and risks." First is the natural type that comes from the sun that has three classes: UV-A and UV-B which have been linked to sunburns, premature skin aging, and the development of skin cancer; and UV-C, a harmful type that has the most energy among the three types. The good news is that UV-C from the sun does not reach the Earth’s surface as the atmosphere absorbs it. 

Man-made UV-C, Capritto describes, is found in UV light sanitizers offered in the market, and claim to kill COVID-19. She says that UV-C works because its light is "strong enough to destroy the genetic material... of viruses and bacteria." While there are currently no published studies that have focused on the effect of UV light on the coronavirus, the contributor says it has been used to disinfect other types of coronavirus. In her article, she shares findings from the National Academies of Sciences, Engineering and Medicine that have proven that UV light has been used “to destroy related coronaviruses, including the one that causes MERS” (Middle Eastern respiratory syndrome). 

The IUVA says that UV light can provide a “multiple disinfectant approach” as COVID-19 can be transmitted through contact with a contaminated surface and then touching a face. It targets the residual contamination that normal cleaning and disinfection can leave behind, the group says, as UV-C has been able “to achieve a high level of inactivation of a near relative of COVID-19’s virus.” It stresses that effectively reaching virus residue is key to UVC application. 

The most important thing you need to know about UV sanitizers: They should not be used to disinfect hands or any part of the human body. The World Health Organization and Mayo Clinic, one of America’s leading hospitals, have both put notice on their websites that UV lamps should not be used to disinfect hands or other areas of the skin as it causes skin irritation and damage to the eyes. UV-light sanitizers should be used only for surfaces. Washing our hands with soap and water or cleaning it with an alcohol-based hand rub is still the most effective way to remove the virus, according to the World Bank. 

Additionally, the World Bank also clarifies that being exposed to the sun or to temperatures higher than 25 degrees Centigrade does not help prevent someone from catching COVID-19. Physical distancing, frequent handwashing and not touching your eyes, nose, and mouth when your hands are not clean will help reduce the possibility of catching the virus.