Health experts have debunked President Donald Trumps idea to potentially use sunlight to treat coronavirus patients. But some social media users say the president is onto something.

An April 24 Facebook post shows an image of what appears to be someone hooked up to an IV that is emanating blue light. The caption claims it shows a "UV radiation" treatment.

"For all you dummies that have absolutely no idea what trump is talking about... INTERNAL DISINFECTANT aka Ultraviolet Radiation is administered into the body as a disinfectant to kill bacteria and viruses and this has been used for a while now," reads the post.

This post was flagged as part of Facebooks efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Facebook.)

(Screenshot from Facebook)

During an April 23 press briefing, Trump floated the idea of using light to treat COVID-19 patients after a Department of Homeland Security official presented a preliminary study that found sunlight kills the coronavirus on certain surfaces. We found no evidence to suggest such a treatment would work on patients, but we wanted to take a closer look at this recent Facebook post.

While the exact origin of the image in the post is unclear, its central claim that some health care providers inject UV light into patients to kill bacteria and viruses is inaccurate. We reached out to the original poster for evidence, but we havent heard back.

We used a reverse image search to scour the internet for the source of the photo in the Facebook post. While we couldnt find the source, we did find several tweets from the same day that included the image.

One user who shared the photo claimed it shows ultraviolet blood irradiation (UBI). The treatment involves drawing a patients blood, then exposing that blood to an external light box before returning it to the body. It was popular in the mid-20th century before the development of antibiotics and was used to treat conditions including pneumonia, tuberculosis, arthritis and asthma..

Now UBI is mainly used in the alternative-medicine community. But UV light is not "administered" into patients bodies, as the Facebook post claims, and experts who have experimented with the treatment say there is no scientific evidence that it kills bacteria or viruses.

Dr. Edzard Ernst, an emeritus professor of complementary medicine at the University of Exeter in the United Kingdom, said the research into UBI and related methods has been limited in scope.

"Yes, there are quite a few papers on UBI and related methods. But most of them are in-vitro studies, while robust clinical trials are missing completely," Ernst wrote in an April 25 blog post. "Needless to say also that UBI is an invasive treatment where lots of things might go badly wrong."

RELATED: Why Trumps comments on using disinfectants, sunlight to treat COVID-19 are wrong

There are three types of UV light: UVA, UVB and UVC. The first makes up the majority of radiation that reaches the Earth, the second can cause sunburn and skin cancer, and the third destroys genetic material.

Applying UVC light to rooms and surfaces has helped some hospitals cut the transmission rate of diseases like MRSA, which can linger in rooms after patients are discharged. The light waves kill bacteria and viruses by disrupting their DNA.

But applying UVC light directly to the body would damage genetic material and cause burns within seconds, experts told PolitiFact. Physicians do sometimes use UVA or UVB light to treat skin lymphoma, but they avoid giving patients too much, as it could increase their chances of developing skin cancer later in life.

"There is a modified version of this in which a drug can be injected ahead of time to increase cell sensitivity to externally applied UV, but in general its not possible to inject UV light itself," said Dr. Angela Rasmussen, an associate research scientist at Columbia Universitys Center for Infection and Immunity, in an email.

Health care providers also sometimes treat donated blood or plasma with radiation before performing infusions to prevent certain diseases, but most American blood banks use gamma rays or x-rays. Thats different from using UV light to treat blood or plasma thats still inside a patient.

"There is no evidence that injecting UV light into the body will kill bacteria or viruses," said Dr. Krutika Kuppalli, a clinical assistant professor in the Division of Infectious Diseases and Geographic Medicine at Stanford University, in an email. "We irradiate blood that has been taken out of the body, but that is different than using UV light. I am not sure what that picture is in the Facebook post."

The Facebook post is inaccurate. We rate it False.

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UV radiation is not a common way to kill viruses and bacteria in the body - PolitiFact