top of page

Busted coronavirus myths take on new life

A series of tips circulating on Facebook and the private messaging app Viber are reinforcing several myths about the novel coronavirus SARS-CoV-2, including the use of bleach, mouthwash and UV light to avoid the contagion.

The 600-plus-word advice, attributed to an unnamed assistant professor in infectious diseases at Johns Hopkins University, came from a “community chat,” was described as an “excellent summary to avoid contagion” and shared March 24.

The tips include at least four myths that have been debunked by the World Health Organization, health experts and fact checkers. Following the advice may harm a person’s health.

The myths:

* Any mix with 1 part bleach and 5 parts water directly dissolves the protein, breaks it down from the inside.
* The virus molecules remain very stable in external cold, or artificial as air conditioners in houses and cars. They also need moisture to stay stable, and especially darkness. Therefore, dehumidified, dry, warm and bright environments will degrade it faster.
* SHINING UV LIGHT on any object that may contain it breaks down the virus protein. For example, to disinfect and reuse a mask is perfect. Be careful, it also breaks down collagen (which is protein) in the skin, eventually causing wrinkles and skin cancer.
*LISTERINE WORKS! It is 65% alcohol.


A fact check by the Pulitzer Prize-winning Politifact said:

There is no scientific evidence that drinking bleach, MMS, or other sodium chlorite products will help cure or prevent disease.

The Food and Drug Administration has issued a number of warnings against drinking bleach solutions such as the Miracle Mineral Solution (MMS), saying it can make one sick. It said:

(T)he FDA is not aware of any research showing that these products are safe or effective for treating any illness. Using these products may cause you to delay other treatments that have been shown to be safe and effective.
The bottom line: Sodium chlorite products are dangerous, and you and your family should not use them.

The Missouri Poison Center said bleach can irritate the skin, the mucous membranes and the gastrointestinal tract.

In its "Interim Recommendations for U.S. Households with Suspected or Confirmed Coronavirus Disease 2019 (COVID-19)," the U.S. Centers for Disease Control and Prevention recommends disinfecting frequently touched surfaces (tables, doorknobs, light switches, countertops, handles, desks, phones, keyboards, toilets, faucets, and sinks) daily, making sure to clean dirty surfaces with detergent or soap with water before disinfecting.

The agency said most common EPA-registered household disinfectants will work. Using diluted household bleach solutions to disinfect surfaces is an option, it said.

The bleach solution for disinfecting surfaces should be "5 tablespoons (1/3rd cup) bleach per gallon of water OR 4 teaspoons bleach per quart of water." That means a ratio of one part bleach and nearly 50 parts water.

If to be used as surface disinfectant, the household bleach should be unexpired, appropriate for the surface and at least 1000ppm sodium hypochlorite. It should be mixed only with water, not with ammonia and other cleansers, the CDC said.

Soap, however, is preferable to bleach in disinfecting surfaces, experts told National Geographic.

Jane Greatorex, a virologist at Cambridge University, said using bleach to disinfect surfaces “is like using a bludgeon to swat a fly.” She also said it can corrode metal and lead to other respiratory health problems if inhaled too much over time.

Lisa Casanova, an environmental health scientist at Georgia State University, told National Geographic:

With bleach, if you put it on a surface with a lot of dirt, that [dirt] will eat up the bleach.


“The COVID-19 virus can be transmitted in ALL AREAS,” WHO said. These include areas with hot and humid weather.

WHO added:

There is no reason to believe that cold weather can kill the new coronavirus or other diseases.


WHO has also busted the myth about mouthwash:

There is no evidence that using mouthwash will protect you from infection with the new coronavirus.

While it acknowledged some brands can eliminate certain microbes for a few minutes in the saliva, “this does not mean they protect you from 2019-nCoV infection.”

A check FactRakers ran on Listerine products shows none of them have an alcohol or ethanol content exceeding 27 percent. The post claims Listerine is 65 percent alcohol.

Original Listerine has 26.9 percent. The alcohol content in other Listerine products with alcohol as inactive ingredient is 10.5 percent (Healthy White) and mostly 21.6 percent such as Ultraclean.

Listerine also produces alcohol-free mouthwash.

Contrary to the post’s claim, the "strongest vodka" is not 40 percent alcohol. Polish-made Spirytus is 96 percent alcohol.

UV light

In answer to the question "Can an ultraviolet disinfection lamp kill the new coronavirus?"

WHO said:

UV lamps should not be used to sterilize hands or other areas of skin as UV radiation can cause skin irritation.

It also said exposure to the sun or to temperatures higher than 25 Celsius degrees does not prevent COVID-19:

You can catch COVID-19, no matter how sunny or hot the weather is. Countries with hot weather have reported cases of COVID-19.   

A BBC explainer said sunlight consists of three types of UV. UVA is what mostly reaches the earth’s surface. It can penetrate deep into the skin and is believed responsible for skin aging. UVB can damage the DNA in the skin, leading to sunburn and eventually skin cancer. UVC, consisting of shorter, more energetic wavelength of light, can destroy genetic material in humans and viral particles.

Quoting an expert on UV light technology, BBC said UVC is "extremely dangerous":

UVC is really nasty stuff – you shouldn't be exposed to it. It can take hours to get sunburn from UVB, but with UVC it takes seconds. If your eyes are exposed… you know that gritty feeling you get if you look at the sun? It’s like that times 10, just after a few seconds.

The BBC article said scientists have recently discovered a promising new type of UVC, far-UVC, which is less dangerous to handle, but it warned that far-UVC hasn't been tested in humans and the vast majority of the UVC lamps on the market do not use it yet.

Specialist equipment and training are needed to use UVC safely, the article said.

Recently, the University of Nebraska Medical Center in Omaha began an "experimental procedure” using ultraviolet germicidal irradiation (UVGI) to decontaminate N95 masks in order to reuse them to address the shortage, according to a New York Times report.

The hospital uses three times the concentration of UV light to decontaminate the masks and has put an elaborate UVGI process in place as safeguard.

Under a Centers for Disease Control and Prevention regulation, decontaminated masks could no longer be certified for use. The CDC, however, issued a new guidance on March 26, saying hospitals may find it necessary to use masks that were not approved by the National Institute for Occupational Safety and Health “as a last resort.”

(Update: A mid-April report of the New York-based Illuminating Engineering Society (IES) said the virus can be inactivated if illuminated with UVC at "the effective dose level" and done with other disinfection methods. The IES, established in 1906, warned of hazards to the eyes and skin and said categorically:

UV-C should not be used to disinfect the hands.)

The best way

The most effective protection against COVID-19 is frequent hand cleaning with alcohol-based hand rub or with soap and water, says WHO.

It said:

By doing this you eliminate viruses that may be on your hands and avoid infection that could occur by then touching your eyes, mouth and nose.

(This article has been updated to include new information.)


Centers for Disease Control and Prevention. (n.d.). Cleaning and disinfection for households:

Interim recommendations for U.S. households with suspected or confirmed coronavirus disease 2019 (COVID-19). Retrieved from

Food and Drug Administration (2019, August 12). FDA warns consumers about the dangerous and potentially life threatening side effects of Miracle Mineral Solution. Retrieved from.

Food and Drug Administration. (2019, August 12). Danger: Don’t drink miracle mineral solution or similar products. Retrieved from

Gibbens, S. (2020, March 18.) Why soap is preferable to bleach in the fight against coronavirus. Retrieved from

Gorvett, Z. (2020, March 28). Can you kill coronavirus with UV light? Retrieved from

Illuminating Engineering Society. (2020, April). IES committee report: Germicidal ultraviolet (GUV)--Frequently asked questions. Retrieved from

Johns Hopkins Medicine. (n.d.) Coronavirus disease 2019: Myth vs. fact. Retrieved from

Kolata, G. (2020, March 20). As coronavirus looms, mask shortage gives rise to promising approach. Retrieved from

Listerine. (n.d.) Products.

Lowe, et al. (n.d.). N95 filtering facepiece respirator ultraviolet germicidal irradiation (UVGI) process for decontamination and reuse. Retrieved from

Missouri Poison Center. (2019, April 15). Bleach. Retrieved from

Putterman, S. (2020, January 30). No, drinking bleach will not ward off coronavirus. Retrieved from

World Health Organization Western Pacific [WHOWPRO]. (2020, February 4). Q: Can gargling mouthwash protect you from infection with the new coronavirus (2019-nCoV)? A: There is no evidence that using mouthwash will protect you from infection with the new coronavirus (2019-nCoV) [Tweet]. Retrieved from

World Health Organization. (n.d.) Coronavirus disease (COVID-19) advice for the public: Myth busters. Retrieved from


bottom of page