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Can UV Light Kill Coronavirus?

Analysis by Dr. Joseph Mercola Fact Checked

can uv light kill coronavirus

Story at-a-glance -

  • UV light can control the transmission of airborne-mediated microbial diseases and may be useful with COVID-19
  • UV light has been used to stop the transmission of C. difficile, tuberculosis, influenza and Ebola
  • UV light has been successful in deactivating MERS, a virus similar to SARS and COVID-19
  • Unlike many medications, UV light can kill resistant viruses that have mutated
  • Sales of UV light devices for decontamination are soaring since the outbreak of COVID-19

Many who are working from home or otherwise isolated during the coronavirus pandemic are looking for some positive news. Well, there is some good news when it comes to controlling the spread of the novel coronavirus now termed COVID-19.

It may be that UV (ultraviolet) light will help dampen this pandemic. UV light is currently used in medical settings,1 wastewater treatment plants2 and food processing.3 Now, as COVID-19 grows, there is increased demand from hospitals and medical facilities for conventional UV lights and variations on such lamps.4 According to Crunchbase News:5

"[S]tartups that disinfect items with UV light are … seeing a boost in sales since the outbreak — and are hustling to keep up with demand as a result. PhoneSoap, a company that makes devices to clean phones and other items with UV light, has seen 1,000 percent growth year over year in the past week …

In about mid-January, PhoneSoap executives began to notice an uptick in interest from overseas on both their website and Amazon. But the surge in sales really came after United States government officials and the Centers for Disease Control started speaking out more about the outbreak and threat to the U.S."

Other startups besides PhoneSoap are also seeing a surge in orders for disinfecting UV products, says Crunchbase:6

"CleanSlate UV, which is based in Toronto and has roughly $2 million in funding, makes devices that sanitize items with UV light. In hospitals, staff usually use CleanSlate UV for items like stethoscopes, badges and phones, and visitors often use it for their phones."

While both PhoneSoap and CleanSlate UV acknowledge that the effectiveness of UV light on COVID-19 has yet to be proven, Taylor Mann, CEO of CleanSlate UV, says:7

"What we can say is UV light has been proven to be effective against previous strains of coronavirus … We just don't know how effective it is against this specific strain."

CleanSlate UV is currently serving more than 80 hospitals in the U.S. and Canada and hospitals in Australia, Hong Kong and Europe.8

Science Backs the Effectiveness of UV Light

The use of UV light for disinfection and decontamination of pathogens is not new. Over a hundred years ago in 1903, Niels Ryberg Finsen won the Nobel Prize in Medicine for opening "a new avenue for medical science" through his discovery of the effect of concentrated light radiation in the treatment of diseases, especially lupus vulgaris.9

UV light is a major tool in the fight against airborne-mediated microbial diseases. According to research published in Scientific Reports in 2018:10

"Airborne-mediated microbial diseases represent one of the major challenges to worldwide public health. Common examples are influenza, appearing in seasonal and pandemic forms, and bacterially-based airborne- mediated diseases such as tuberculosis, increasingly emerging in multi- drug resistant form.

A direct approach to prevent the transmission of airborne-mediated disease is inactivation of the corresponding airborne pathogens, and in fact the airborne antimicrobial efficacy of ultraviolet (UV) light has long been established.

Germicidal UV light can also efficiently inactivate both drug-sensitive and multi-drug-resistant bacteria, as well as differing strains of viruses."

Hospitals decontaminate rooms that housed patients with dangerous and contagious infections such as C. difficile with UV light, according to The New York Times.11 During the Ebola outbreak in 2014, the University of Nebraska Medical Center successfully relied on UV light disinfection, reports the Times.12

The center allows large UV lamps to "shine for three to five minutes," explained John Lowe, the medical center's assistant vice chancellor for health security training and education, to the Times. "It disinfects anywhere it can shine."13

At the University of Massachusetts Memorial Medical Center, Dr. Richard Ellison, the hospital epidemiologist, concurs about the effectiveness of UV light. "The research supports this type of cleaning," he says.14

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UV Light Has Worked With Similar Coronaviruses

SARS (severe acute respiratory syndrome) is an animal-related respiratory illness caused by a coronavirus that surfaced in Asia in 2003. Though it was largely contained by 2004,15 a similar disease, MERS (Middle East Respiratory Syndrome), surfaced in 2012, originating in Saudi Arabia.16 COVID-19 shows "significant overlap" with both SARS and MERS, says Science Daily.17

The good news is that UV light has shown positive effects against MERS in scientific studies. According to research published in the journal Transfusion, two different UV light devices reduced MERS infectivity in platelets and plasma, as well as infectivity from the Ebola virus.18 Ebola is a rare, sometimes fatal illness first reported in Africa.19

A study published in Transfusion Medicine to determine if UV light could reduce MERS-Coronavirus (MERS-CoV) transmission by human platelet concentrates also found effectiveness combined with Amotosalen,20 a light-activated DNA and RNA crosslinking agent:21

"Complete inactivation of MERS-CoV in spiked platelet units was achieved by treatment with Amotosalen/UVA light with a mean log reduction of 4·48±0·3. Passaging of the inactivated samples in Vero E6 showed no viral replication even after nine days of incubation and three passages. Viral genomic …

Amotosalen and UVA light treatment of MERS-CoV-spiked platelet concentrates efficiently and completely inactivated MERS-CoV infectivity (>4 logs), suggesting that such treatment could minimize the risk of transfusion-related MERS-CoV transmission."

Novel Uses of UV Light Disinfection Are Seen

Hospitals are well aware of the benefits of UV light in cleaning rooms and equipment but manual cleaning may not be as thorough as necessary. That is why the use of UV-disinfection robots is being explored. According to Interesting Engineering:22

"Maintaining a clean and safe healthcare environment is a top priority, and while significant progress has been made in sanitization methods, major improvements must still be made. According to the CDC even with modern sanitization protocols, on any given day, about one in 25 hospital patients will acquire at least one healthcare-associated infection.

Current manual cleaning methods are nearly helpless in combating against bacteria, but the battle is not lost. Infection prevention technologies are giving rise to a new era of ultra-clean hospital's and emergency care facilities with the implementation of highly-efficient UV-disinfection robots …

The robots are fast and efficient, able to eliminate far more bacteria than humanly possible. Their ability to move around enables them to attack shadowed areas where many harmful organisms tend to manifest in places that are often missed by sanitization teams."

Since COVID-19 can spread in venues other than medical settings, airlines are also exploring UV light disinfection. Boeing is developing a self-cleaning lavatory that is disinfected after every use with UV light, effectively killing 99.99% of pathogens on all surfaces in three seconds. The lavatory is also hands-free. According to Travel and Lesiure:23

"'The UV light destroys all known microbes by literally making them explode,' Boeing Research & Technology engineer Jamie Childress said in a statement. While Boeing says this particular type of light isn't harmful to humans, the cleaning system is designed only to turn on when the bathroom door is closed and unoccupied."

More Advantages of UV Disinfection

One reason pathogens are so difficult to kill is that they mutate and develop resistance, which renders antiviral medications and antibiotics developed especially for them useless. Not so with UV light disinfection, says a UV device maker. According to Clean Technica, referring to the Scientific Reports study published in 2018:24,25

"Another advantage of … [the] UVC study is that it's both effective against bacteria which have evolved resistance to common drugs and it's very unlikely that diseases and viruses could evolve to be resistant to it due to effective limitations on their scale."

The goal of virus eradication is to stop the viruses from replicating. Digital Trends reported:26

"Viruses don't reproduce on their own, but they do have genetic material, either DNA or RNA. They reproduce by attaching to cells and injecting their DNA …

UV light can cause [viruses'] thymine bases to fuse together, scrambling the DNA sequence and essentially throwing a wrench into the machinery. Since the DNA sequence is no longer correct, it can no longer replicate properly. This is how UV light annihilates viruses, by destroying their ability to reproduce."

UV light may be an improvement over current disinfectants, especially those used outside. Worldwide reports say the most commonly used outdoor disinfectant against COVID-19 is a diluted solution of sodium hypochlorite known as household bleach. But there are drawbacks. Says Science magazine:27

"[I]t's unclear whether bleach destroys coronaviruses outside, and if it does kill them on surfaces it's unclear whether it would kill viruses in the air. Bleach itself breaks down under ultraviolet (UV) light. Then again, [Juan] Leon [an environmental health scientist at Emory University] says UV light seems to destroy coronaviruses as well …

There may even be downsides to widespread overzealous disinfection with bleach, notes Julia Silva Sobolik, a graduate student in Leon's lab. 'Bleach is highly irritating to mucous membranes,' Sobolik says. That means people exposed to sprayed disinfectants — especially the workers who spray them — are at risk of respiratory troubles, among other ailments.

Sobolik notes that an October 2019 study in JAMA Network Open found that nurses who regularly used disinfectants to clean surfaces were at higher risk of chronic obstructive pulmonary disease.28 A 2017 study linked exposure to disinfectants to asthma to adults in Germany.29"

UV Light Can Help Personal Protective Equipment

Shortages of personal protective equipment (PPE) for front line medical staff are widespread during the COVID-19 pandemic. According to The New York Times, protective facemasks for health care workers at the University of Nebraska Medical Center are now being decontaminated with UV light for reuse.30

"'We are making the best of bad choices,' said Dr. Mark Rupp, the medical center's chief of infectious diseases. He feels confident that the masks will still protect health care workers. 'The data is very clear that you can kill and inactivate viruses with UV germicidal irradiation,' he said. 'It is also very clear that you will not damage the respirators.'"

Other hospitals are also treating protective face masks with UV light, says the Times.31 Years ago when I was in college I got some sense of the power of UV light first hand. I developed the nail infection called onychomycosis characterized by yellow nail discoloration.

These infections are common but notoriously hard to treat even with powerful and sometimes risky oral antifungal drugs. In my case, my intensive running and lack of understanding of optimal diet probably contributed to the condition.

Medication treatments were unsuccessful, but, to my delight, my infection disappeared after frequent, daily doses of sunshine on my toes. Looking back, it makes perfect sense that sunlight would remove the infection since UV light is a very potent germicide.

For industrial uses, mere exposure to sunlight won't do the trick — lamps emitting UV are required. They "could really be beneficial in disrupting disease transmission," says Shawn Gibbs, who has studied UV disinfection at the Indiana University School of Public Health in Bloomington.32 Let's hope UV light can be used to fight COVID-19.