Can Sunlight Kill the Coronavirus? Here's What Doctors Say

Last month, President Donald Trump and his administration alluded to new research claiming that sunlight or UV radiation was effective in killing or weakening COVID-19. So far, the specific research results they were referencing have not been released, but experts warn that there is no actionable advice to take from their press conferences. Doctors say that the dangers posed by extreme UV radiation outweigh any potential benefits.

During his coronavirus task force briefing on April 23, Trump cited "emerging results" from research conducted by the Department of Homeland Security, indicating that sunlight, heat and humidity could all weaken the pandemic. Acting homeland security undersecretary for science and technology, Bill Bryan, went into more detail, but the research in question has not been published yet. In the meantime, reached out to infectious disease experts to ask about this idea. They seemed to agree that, while sunlight might help to weaken the virus, its applications would be limited.

Dr. Amesh A. Adalja confirmed that UV light does decrease the viability of viruses in general, including COVID-19. However, Adalja said: "That doesn't mean people with COVID-19 who expose themselves to UV light — or sunlight, which contains UV radiation — will get rid of the infection."

Moreover, UV radiation comes with serious health risks of its own, including severe damage to skin cells and possibly skin cancer. This fact seems to negate Trump's suggestion that "hitting the body with a tremendous" ultraviolet light could be a treatment, as well as his idea of getting "the light inside the body... either through the skin or in some other way."

Bryan's comments pertained more to the virus' lifespan on surfaces or in the air. He claimed that the department's research showed high temperatures, humidity and sunlight to be "generally less favorable to the virus." However, health experts say that the primary form of transmission is person-to-person.


Since that press conference, the World Health Organization has responded to the president's statements on its "myth busters" web page. It notes: "Exposing yourself to the sun or to temperatures higher than 25C degrees DOES NOT prevent the coronavirus disease. You can catch COVID-19, no matter how sunny or hot the weather is. Countries with hot weather have reported cases of COVID-19."

Trump has since discontinued his daily press briefings on the pandemic. For the latest information on the coronavirus pandemic, visit the websites of the CDC and the World Health Organization.