US govt reveals information on sunlight study on virus
29 April, 2020
The US Department of Homeland Security revealed to AFP on Tuesday new technical details regarding its highly anticipated study into how ultraviolet radiation destroys the brand new coronavirus, saying that its experiment had accurately mimicked natural sunlight.
A summary of the study was presented the other day at the White House, with some scientists calling for caution until a more comprehensive report was made public.
US President Donald Trump raised eyebrows last week when he used his daily live national press briefing to ask whether light could turn into a medical treatment.
"Supposing we hit the body with a significant -- be it ultraviolet or perhaps very powerful light," he said. "Supposing you brought the light inside the body, that you can do either through the skin or in some other way."
Trump continued on to suggest that persons inject disinfectants to cure the virus, an idea that health authorities quickly shot down.
DHS official William Bryan had briefed the media that the quantity of virus on a non-porous surface shrunk by half in only two minutes when sunlight was present, the temperature was 70-75 degrees Fahrenheit (21-24 Celsius) and humidity was 80 percent.
The volume of virus suspended in air shrunk to half its amount in just 1.five minutes at room temperature and 20 percent humidity, he added.
These eye-catching results surprised authorities because the majority of the UV light within natural sunlight belongs to a subtype called UVA, which in turn causes human skin to tan and age but has not generally been proven bad for viruses, David Brenner, director of the guts for Radiological Research at Columbia University Medical Center, told AFP.
On the other hand, part of the spectrum called UVC is specially adept at warping the genetic material of animal and virus cells and is widely used in sterilizing lamps, nonetheless it is not present in sunlight since it is filtered out by the Earth's atmosphere.
Asked for further information on the sort of UV light that was used, Lloyd Hough, a DHS scientist overseeing the test, said: "The spectral range of light that was used was designed to approximate natural sunlight that you'll be prepared to see at noon at sea level at a mid-latitude location (e.g., mid-Atlantic, 40 degrees N) on the first day of summer.
"More specifically, it approximates the wavelengths of light predicted by the National Center for Atmospheric Research's (NCAR) Tropospheric Ultraviolet and Visible (TUV) Radiation Model for noon at 40 degrees N latitude at sea level on June 21st in selection of 280 and 400 nanometer wavelengths."
The wavelengths specified pertain and then long- and medium-wave ultraviolet, generally known as UVA and UVB -- the UV components of sunlight that penetrate the atmosphere -- rather than UVC.
Paper coming soon
A DHS spokesman added that the test -- that was conducted at the National Biodefense Analysis and Countermeasures Center in Maryland -- was carried out on droplets of simulated saliva on a stainless surface.
Brenner, who's himself performing research into another section of the UV spectrum called far-UVC, which kills microbes without penetrating human skin, said the DHS findings didn't comport with previous research.
"You will find a peer-reviewed paper in the literature from the FDA [Food and Drug Administration] showing the sooner SARS-CoV virus did not react to UVA light [though it did react to UVC light]," he said, adding it really is "reasonable to assume that all coronaviruses respond roughly the same manner to light."
The results as presented were "straining credulity," he added.
But a DHS spokesman said that study would soon be submitted for peer review and published in scientific journals.
"While the email address details are still undergoing a rigorous scientific review, we felt it important to share information on the emerging trends that are being discovered inside our tests," the spokesman said.
Source: www.thejakartapost.com
TAG(s):