UV LIGHT AND COVID-19

In recent months, the topic of UV light and Covid-19 has been widely explored.  If you search the internet for data on whether UV kills the coronavirus, you will get 14,000,000 results.  Although UV light was used to disinfect air, water and surfaces for decades, the pandemic launched a higher level conversation on the topic.  So, does UV kill the coronavirus? I scoured the internet to find an answer to that question.

So, How Many Coronaviruses are There?

In studies on the effects of UV on the coronavirus that causes Covid-19, the data continually referred to “coronaviruses”, plural.  So, how many coronaviruses are there? It turns out the answer is, several:

• 229E (alpha)
• NL63 (alpha)
• OC43 (beta)
• HKU1 (beta
• MERS-CoV, beta virus causes Middle East respiratory syndrome (MERS)
• SARS-CoV, beta virus causes severe acute respiratory syndrome (SARS)
• SARS-CoV-2, which causes COVID-19

To further complicate things, until recently, the SARS-CoV-2 virus responsible for the current Covid-19 pandemic was only in animals. 

So, now that the SARS-CoV-2 coronavirus has jumped to humans, scientists had to distinguish between the old SARS-CoV-2 and the new SARS-CoV-2. They dubbed the new SARS-CoV-2 the “novel” coronavirus.  Therefore, when reviewing data on UV Light and Covid-19, I needed to filter down to studies that involved the SARS-CoV-2 novel coronavirus.

What is UV Light?

UV stands for ultraviolet and refers to electromagnetic radiation.  Sunlight is the main source of UV radiation; it’s the reason you slather on SPF before

you go outside.  But there are different types of ultraviolet radiation, UVA, UVB and UVC.  Although all 3 categories are dangerous, on a scale of bad to really-really bad, UVA radiation would be bad and UVC would be categorized as really-really bad.

The rays of sun that make it to the ground are mostly UVA and a very small percentage of UVB.  The sun also gives off UVC rays. Luckily UVC is blocked by the earth’s ozone layer. However, you need UVC radiation for the purposes of sterilization.

UV Uses

UV lights are used for many applications.  The blue light gadget the dentist shines on your teeth to speed up whitening is an example of a UV light.  The nail dryer or the tanning bed at the salon; indoor garden lighting, black lights and restaurant germicidal lamps are just a few more examples.

But ultraviolet-C light (UVC) has made the most significant impact in killing bacteria and viruses.  Since the 1950s, water treatment plants have successfully disinfected drinking water using UV light; but the practice dates back to the early 1900s.  Hospitals use UV to sanitize equipment and operating rooms; as well as in HVAC systems to kill mold, bacteria and reduce odors for better air quality.

How Does UV Work with Viruses?

How does UV work with viruses? The short answer is, shine the UVC light on a surface and in seconds bacteria, mold and viruses are dead.  But the process is much more complex.

The reason ultraviolet light is effective is because the radiation damages the DNA in bacteria and mold; and destroys RNA in viruses which prevents the viruses from reproducing.   It also demolishes the outer protein layer of a virus, preventing it from attaching to a host (you).

However, for all that to happen, the UVC must be administered in the correct dose and wavelength.  But there is another problem, ultraviolet radiation is dangerous to humans.  It is a carcinogen which can cause cancer in humans and can also damage vision.  So, what’s the answer?

Enter far-UVC.  Researchers at Columbia University Irving Medical Center found that creating ultraviolet light at a specific wavelength (222 nanometers) was the solution.  According to Dr David Brenner, Ph.D., D.Sc., theoretical physicist and director of the Center for Radiological Research at Columbia University, far-UVC could still sanitize a space but without penetrating “the tear layer of the eye or the outer dead-cell layer of skin, so it cannot reach or damage living cells in the body.” 

Does far-UVC Kill the SARS-CoV-2 Coronavirus?

So, the big question, does far-UVC kill the SARS-CoV-2 coronavirus. Scientists at Columbia University, Former NASA scientist and HealtheLighting chief scientific officer Fred Maxik, all point to yes.  Although current SARS-CoV-2 studies are extensions of prior coronavirus research, preliminary data is pointing to the same conclusions. 

Columbia University’s, Dr David Brenner, was quoted in a June 24, 2020 Columbia University news article stating “Far-UVC light doesn’t really discriminate between coronavirus types, so we expected that it would kill SARS-CoV-2 in just the same way”.

Other Fascinating UV Light and Covid-19 Articles

Kramer Engineers has designed a wide range of projects utilizing UV lighting for sanitation of water, HVAC, hospital, lab and cleanroom design. So, this topic hit close to home.  If you are interested in additional reading on UV light and its effects on the spread of Covid-19; the following are links to some fascinating news articles on the topic.  The links include a July 8, 2020 piece by Dr Liji Thomas, MD suggesting a link between UVA (sunlight) and reduction of Covid-19.