BEIJING, May 8 (Xinhua) -- Some rumors claim that ultraviolet (UV) light and vitamin C can be used as medical treatments for COVID-19.

The fact is, experts have not found enough scientific evidence that the two can help people fight off the novel coronavirus.

"We would like to inform the public that there are no protocols to advise or permit the safe use of UV light directly on the human body at the wavelengths and exposures proven to efficiently kill viruses such as SARS-CoV-2," said a joint statement by industry groups the International Ultraviolet Association and RadTech North America.

Scientists believe that UV light is quite dangerous if used directly on human bodies.

"UV radiation can cause skin irritation and damage your eyes," said the World Health Organization.

"It is not safe to use UV sanitizers on your body," warned the U.S. National Academies of Sciences, Engineering, and Medicine.

"For years, we've used UV on air and surfaces and on hospital rooms, with no humans in the room," Jim Malley, a UV light expert and professor of civil and environmental engineering at the University of New Hampshire, told USA Today. "We protect ourselves in the laboratory with face shields and gloves to keep the UV away from our eyes and our skin."

Besides, experts remained skeptical about the UV blood irradiation (UBI), which involves withdrawing a measure of blood and exposes it to UV light.

The UBI is "an invasive treatment where lots of things might go badly wrong," wrote Edzard Ernest, professor emeritus at the University of Exeter, in April, adding that robust clinical trials on the UBI "are missing completely."

As for vitamin C, many scientists have suggested there is less evidence that it grants immunity against the virus, or alleviates symptoms for COVID-19 patients given a high dose.

William Schaffner, professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center in the U.S. state of Tennessee, told The New York Times no evidence suggests that vitamin C supplements can help prevent COVID-19.

"If there's going to be an advantage, it's going to be very modest," he said.

Also, no results are yet available for the clinical trial launched on Feb. 11 by researchers from Zhongnan Hospital of China's Wuhan University to test the efficacy and safety of vitamin C infusions for the treatment of COVID-19 patients.

According to media reports in April, Charles Mok, a 56-year-old Michigan doctor who claimed in multiple videos that vitamin C infusions supposedly reduce the severity of symptoms and the duration of illness, as well as boost the immunity of those who have a high risk for contracting COVID-19, has been charged with health care fraud and conspiracy to commit health care fraud.