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Infectious disease

How we know disinfectants should kill the COVID-19 coronavirus

The novel virus is one of the easiest virus types to deactivate, though SARS-CoV-2–specific data are lacking

by Kerri Jansen
March 13, 2020

 

20200313lnp1-spray.jpg
Credit: ADragan/Shutterstock
Under the US EPA's emerging viral pathogen program, makers of disinfectant products can request approval to claim a product is expected to kill the novel coronavirus based on its ability to kill similar viruses.

The spread of the coronavirus disease COVID-19 has spurred a surge in sales of cleaning and disinfection products. The Centers for Disease Control and Prevention (CDC) recommends regular cleaning of frequently touched surfaces, along with thorough hand washing—both standard practices for helping slow the spread of viruses and bacteria. But consumers will be disappointed if they go looking for a product that specifically promises to kill SARS-CoV-2, the virus that causes COVID-19.

Although there’s good evidence the novel coronavirus is one of the easiest types of viruses to kill, scientists are still determining its exact nature and how big a role surface transmission plays in its spread. As researchers rush to understand the new pathogen, the US EPA is working to provide the public with information about disinfectants that can help slow its spread. Such claims won’t be allowed in brick-and-mortar stores, though, until more testing can be done.

C&EN has made this story and all of its coverage of the coronavirus epidemic freely available during the outbreak to keep the public informed. To support our journalism, become a member of ACS or sign up for C&EN's weekly newsletter.

Understanding exactly how a new virus spreads and persists in the environment takes time, resources, and virus samples for research—all of which are spread thin in the early weeks and months of an outbreak. That lack of data creates challenges both for people seeking advice about how to avoid this new disease, and the experts and organizations offering that advice.

“Everyone puts in a word of caution in there that we don’t really know, because we don’t have enough data yet,” says Charles Gerba, a microbiologist at the University of Arizona who studies how viruses spread in indoor environments.

On March 3, the EPA released a list of antimicrobial products for use against SARS-CoV-2, under an emerging viral pathogens program developed for just this kind of scenario. (The EPA regulates antimicrobial products as pesticides.) Under the program, which was introduced in 2016 and activated for the first time in January, makers of disinfectants can request approval to claim a product is expected to kill a particular virus based on its ability to kill similar viruses. Once an outbreak has been identified and the identity of the virus is confirmed by the CDC, approved products are temporarily permitted to distribute information about using the product for the emerging pathogen. The claim appears in a standard format such as: [Product name] has demonstrated effectiveness against viruses similar to SARS-CoV-2 on hard, nonporous surfaces. Therefore, [product name] can be used against SARS-CoV-2 when used in accordance with the directions for use.

According to the EPA, these statements are intended to “inform the public about the utility of these products against the emerging pathogen in the most expeditious manner.” The emerging pathogens program sidesteps the lengthy review process that is typically required for vetting disinfectant efficacy claims, which requires the establishment of a standardized protocol and testing with the actual virus or an EPA-approved surrogate. At this time, an EPA spokesperson says, no companies have sent the agency any efficacy data on the novel coronavirus or any surrogates.

Speed is of the essence, because surfaces such as doorknobs, countertops, and electronic equipment can transmit viral and bacterial diseases. According to the CDC, SARS-CoV-2 is believed to spread primarily person-to-person through airborne respiratory droplets. But it may be possible for the virus to spread on surfaces, too. Scientists know that similar respiratory viruses expelled into the air by coughing, breathing, or speaking can settle on surfaces, where they can linger in an active state for days, protected in a cozy covering of mucus. Although scientists aren’t sure yet how long the novel coronavirus remains active on a surface, one study done in a hospital found that similar coronaviruses can persist on hard surfaces like glass, metal, or plastic for up to 9 days (Journal of Hospital Infection 2020, DOI: 10.1016/j.jhin.2020.01.022). Another study, recently published on medRxiv and not yet peer reviewed, found that SARS-CoV-2 remains stable on plastic and stainless steel for 2–3 days. (MedRxiv 2020, DOI: 10.1101/2020.03.09.20033217). The authors also published their data in a correspondence in the New England Journal of Medicine (2020, DOI: 10.1056/NEJMc2004973).

During that time the virus can potentially be spread to anyone touching the surface, and to whatever they touch next. People tend to underestimate how quickly a virus can spread through a building and beyond via touched surfaces, Gerba says.

Gerba notes that technological advancements like large airliners, massive sports stadiums, and the proliferation of self-service kiosks have made it easier for diseases to spread rapidly. Mobile devices like smartphones can pick up germs from contaminated hands and then offload those germs later on to spread in a new location.

Enveloped viruses like SARS-CoV-2—which rely on a protective lipid coating—are the easiest type to deactivate. In contrast with many gastrointestinal viruses like norovirus which have a tough protein shell called a capsid, viruses with this fatty wrapping are relatively vulnerable.

“It’s much more sensitive. It’s sort of a wimpy protective shell,” says virologist Seema Lakdawala of the University of Pittsburgh.

There are a few ways to burst this flimsy shell. Alcohol-based products disintegrate the protective lipids. Quaternary ammonium disinfectants, commonly used in health-care and food-service industries, attack protein and lipid structures, thwarting the pathogen’s typical mode of infection. Bleach and other potent oxidizers swiftly break down a virus’s essential components.

The EPA’s list of disinfectants presumed effective against SARS-CoV-2 contains several dozen antimicrobial products including ready-to-use sprays, concentrates, and wipes. Each has been shown to be effective against at least one small or large nonenveloped virus, which are considered harder to kill than the enveloped variety. And that list is likely to grow; on March 9, the EPA announced it was expediting emerging pathogen-related requests that met certain requirements.

But consumers are unlikely to see such language on product labels any time soon. The EPA’s emerging viral pathogens program limits the places disinfectant makers can publish such a claim to off-label sources like websites, company help lines, and social media. Responding to public comments on an early draft of the program, the agency explained that this measure enables claims to be quickly removed if necessary. Product makers may also include the claims in technical literature distributed to health-care facilities, where it’s expected its recipients would have the background to put such claims in context.

The Clorox Company, which has several products on the EPA list, names three on its website’s coronavirus cleaning page along with the following statement: “Per the EPA Emerging Pathogen Policy, these products can be used against SARS-CoV-2 when used as directed.” The cleaning products giant has shared information about those products’ efficacy since late January, when the EPA activated its emerging viral pathogens program, according to a Clorox representative. The company’s standard practice is to seek pre-approval for the program when registering new products.

Of course, for the products to be effective, they should be used according to directions. The recommended contact time for common disinfectants ranges from 30 s to 10 min. Wiping them off too soon might clean the surface without disinfecting it, says Brian Sansoni of the American Cleaning Institute, a trade group for the cleaning products industry.

“Each disinfectant product—be it a spray or wipe, for instance—is formulated differently,” Sansoni says. Different products require different amounts of time to effectively kill a particular germ or virus.

Cleaning electronic devices like smartphones can be particularly challenging, with concerns about damaging sensitive components and coatings.

“Don’t use bleach,” Apple directs in recently released cleaning guidance for its products. The tech company says it’s safe to gently wipe keyboards and displays with a 70% isopropyl alcohol wipe or Clorox Disinfecting Wipes.

Gerba recommends disinfecting wipes for cleaning other surfaces, too. With spray-and-wipe products, consumers often wipe the product up before it can do its job. But in studies done in people’s homes, they are more likely to let a surface air-dry after swabbing it with the wipe, giving the disinfectant compounds time to work.

“Disinfecting wipes win hands-down,” he says.

UPDATE

This story was updated on March 18, 2020, to include a link to a correspondence in the New England Journal of Medicine reporting data on how long the novel coronavirus survives on different surfaces.

This story was updated on March 16, 2020, to include the link to the EPA's most recent list of antimicrobial products for use against SARS-CoV-2.

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Comments
(March 14, 2020 3:09 PM)
Hydrogen Peroxide (3%) kills viruses too!
Rod Owen (March 15, 2020 3:31 PM)
The article mainly focus on alcohol and wipes. Neither now are readily available. What is needed is practical ad vice and instructions on use of common cleaners such as ammonia and Clorox in a common large bottle. Often sprays and wipes are no longer available. Need to know the best way to make our own sprays and wipes from available products.
Jyllian Kemsley (March 16, 2020 5:51 PM)
The above comment from Rod Owen could be read to suggest that people combine ammonia and bleach (Clorox or otherwise). Mixing cleaners is generally a bad idea, because doing so can generate toxic gases or result in an explosion. You can read more in this story:

Accidental mix of bleach and acid kills Buffalo Wild Wings employee
https://cen.acs.org/safety/consumer-safety/Accidental-mix-bleach-acid-kills/97/i45
Hope (March 17, 2020 1:45 PM)
I don't read it that way at all. I myself use ammonia to clean with more than bleach, as it seems to annoy my lungs less while cleaning. I have a very old home recipe for an ammonia based cleaner (again, there is NO bleach in it), but am having a very hard time determining if ammonia will kill the virus, and if so, can it be diluted and by how much and still have the desired effect. Everything I read is about bleach, which is sold out everywhere. If ammonia can help people, I think folks should start talking about that more & how so. It's been used as a disinfectant for decades, but most people forget about it.
Kyreen Cooper (March 17, 2020 10:16 AM)
I am under my understanding from what I’ve learned growing up is bleach and fire are the only things that kill germs and viruses. If I’m wrong please correct me.
Mark Jeansonne (March 18, 2020 11:52 AM)
Check 409 cleaner. The one I just bought contains the Quaternary ammonium disinfectant. Wet a paper towel with this. Should be the same as a wipe.
Mati Feuss-Green (March 20, 2020 12:09 PM)
Use a 10% bleach solution. That’s what hospitals use. Spray it on, leave it for a couple minutes and wipe it down. Let air dry.
jean orban (March 26, 2020 3:32 PM)
uses this in nurse clinic when still working as RN in 1979 after Hiv clients came for care. was standard care
Jeff Bodell (March 15, 2020 9:07 PM)
Can glass cleaner with ammonia be effective in killing this virus type. Also, many EPA approved Hospital disinfectants that kill HIV and other Micro organisms be effective ? Thank you.
Michael Webb (March 19, 2020 11:57 AM)
Commercial window cleaner formulations I have been familiar with contain far less than the 60% alcohol currently being recommended for disinfection. Ammonia levels are also pretty low, so I would be very skeptical window cleaners would have much anti-viral activity, even for relatively fragile varieties. OTOH, it seems to me that if a virus is removed from a surface (facilitated by plain soap and water for example) the surface becomes just as noninfectious as if it is 'killed in place'. For my part, if I did not have access to a product claiming anti-viral properties I would resort to a regular cleaning product. That's what I'm doing with my hands' surface- about 12-14 times a day now- which otherwise would just be a waste of time.
Andrew Franz (March 17, 2020 10:00 AM)
Ozone
Garth (March 18, 2020 6:49 AM)
Like Rod, I also want to know if Windex or other glass cleaners containing ammonia and alcohol kill coronavirus. Everything else is sold out all the time now where I live. Ive been using Windex to clean all surfaces for about a week now. Am i wasting my time? Am i protecting my family? Nobody seems to want to answer this specific question. I don’t care about the EPA’s website and their list or anything else. Just can someone with a scientific background please answer: Does windex kill corona viruses?
Adam (March 20, 2020 5:05 PM)
Lactic acid should do it 0.19% - multi surface has that. Most things are going to kill it, but some may make it stronger (kidding). It all works, the prob is simply that it is contagious and new, so our bodies didn't have previous immunity.
Tony Addison (March 22, 2020 2:41 PM)
For Garth & Rod: We have for years wiped kitchen benches down with Windex or a similar cleaner. Doing this will help remove the bacteria, "dirt" and other microorganisms. However, I very much doubt that such spray detergent products can kill viruses, especially on cold surfaces like a benchtop. So we follow up the cleaning with a wipe-down using 70-100% alcohol. I just checked the "contents" tag on a Windex bottle: it's basically just dilute detergent. Be aware that to sanitize, you need to use the alcohol at at least the 65% or so level. High-strength supermarket ammonia solution presumably makes life uncomfortable for microorganisms, as it's indeed biocidal because of its alkalinity, but I note that it's not on EPA's list of disinfectants, maybe(?) because to get it strong enough to actually be effective, you'd probably need to wear a gas mask ?!
Lou (March 18, 2020 3:28 PM)
I've carefully read the 11 page listing of cleaners effective against viruses such as Covid 19. The range of ingredients and products listed suggests that ANY commonly available OTC cleaner should be effective, if used according to instructions. The active ingredients on the list are used in all commercial sanitizing cleaners, suggesting that (a) they work, and (b) they're already regulator-approved for such use. So don't worry and fret. Just use your cleaner of choice and relax.
James Lewis (March 18, 2020 3:33 PM)
As a research biophysical chemist, I worry about using either chlorine or ammonia based cleaners indoors to mitigate a lung pathogen. Quaternary ammonium based cleaners seem less likely to irritate the lungs. Overall, let us not make matters worse with the preventive measures we take.
Charles Heimerdinger (March 19, 2020 2:05 AM)
One fluid ounce of store-strength chlorine bleach (NaOCl) mixed with one gallon of water will give about a 500 ppm solution of free available chlorine which is then extremely effective at killing bacteria and deactivating viruses on porous surfaces. ADBACs are mild but take longer to act than NaOCl and are much more expensive than NaOCl.

H2O2 is more costly than NaOCl and for those who know how each are manufactured (and I do) it's obvious that H2O2 is not an environmentally "friendly" product, and that's a fact. As an aside, bleach is used in potable water disinfection (and oxidizes H2O2 to H2O and O2, but I digress). None of the other chemicals are suitable for the same purpose, also a fact.

"Every man has a right to his own opinion but no man has a right to be wrong in his facts." -Bernard Baruch-

"A little learning is a dangerous thing." -Alexander Pope-
loyce hairston (March 19, 2020 3:54 PM)
I wish to thank Charles Heimerdingar for the formula to use with common household bleach and water. I am making my own now due to knowing correct formulation to both kill viruses and hopefully not my lungs! THANK YOU!
Karen (March 22, 2020 3:00 PM)
Is that the same ratio of ammonia to water
Andrea DiCiesare (March 19, 2020 8:54 PM)
Will 409 multi-purpose kill coronavirus?
Francis (March 20, 2020 12:46 PM)
What do you think on killing viruses without uses these chemicals? Perhaps the UV lamp, Infrared Light that goes to 660nm to 850nm deep penetration red light?

https://infraredforhealth.com/potential-cure-for-corona-virus-via-infrared-heat/
Tony Addison (March 21, 2020 1:37 PM)
Quarternary ammonium salts like benzyltrialkylylammonium salts are potent biocides. However, as far as I know, it's not proven that they are particularly effective at the low levels (0.2%) found in household cleaners. Presumably, once you get up to the 10%–15% level, they are more useful. Peroxides like hydrogen peroxide or peracetic acid are quite effective; I've recently seen (Philadelphia Inquirer) a recommendation for "oxiclean", which is a percarbonate (peroxycarbonate) salt. However, its mode of action likely relies on the release of hydrogen peroxide, and I've found no information on how fast or slow that is at room temperature. As its solutions have a fair shelf life, that suggests the release is slow, so in the absence of any evidence that it's effective, I'd not bank on it.
Cathy (March 21, 2020 7:52 PM)
Although the term "kill" is used--is that the precise term? I thought viruses were not considered alive.
Greg Rudd (March 22, 2020 11:56 PM)
I’d enjoy more chemistry in such an article. Some
discussion of which compounds have been shown to damage virus lipid capsules and etc. maybe a reference to a review article or something.
Brian Reed (March 23, 2020 3:00 AM)
I personally would prefer tea tree oil or orange oil...there is a great product called EnviroOrange concentrate you mix with water for cleaning/disinfecting.
Michael Webb (March 23, 2020 9:32 AM)
The EnviroOrange website makes claims for cleaning/degreasing, but I don't see a disinfecting claim. As I said before, cleaning is an effective viral countermeasure, especially for hard surfaces, but to make a disinfecting claim a product has to have efficacy data reviewed by the EPA.
Michael Webb (March 23, 2020 9:18 AM)
Just to point out, the EPA registration for disinfectants is intended to limit product claims absent scientific data that the chemistry actually is effective in the product application. So speculations about this our that 'ought to work' should take a back seat (especially in a technical forum) to registered products which presumably have efficacy data.
Lyn (March 23, 2020 4:36 PM)
What about the use of hydrogen peroxide to kill COVID19. What percent solution is required? - more than 3%?, then let it sit and dry. I do have access to 35% food grade stuff. I know the ratio is one h2o2 to 11 water for 3% solution...so I'm erring towards more like 10% solution. Any thoughts? Thank you.
Tony A. (March 26, 2020 5:43 PM)
It seems to me that 3% peroxide should be OK. As you say, wipe it on, let it dry and work in the meantime. 35% is lab grade - pretty vicious stuff, which can burn you; 3% much safer to use.
Eboy (March 23, 2020 5:43 PM)
I read that coronavirus can't survive on copper for more than six hours, which means the chemical properties in copper can be used to make a vaccine against covid 19
Tanya B. (March 23, 2020 7:12 PM)
I just want to know if ammonia is safe and effective? Just a “YES” or “NO” would suffice:)
Shawn F (March 25, 2020 3:03 PM)
Tanya B, I do too! I have two jugs of ammonia. Can I use them? And, if with how much water should I dilute it? Can SOMEONE answer this question?
Jacqueline (March 25, 2020 2:53 PM)
Alcohol, Hydrogen peroxide (3%-NO higher), bleach (unexpired and properly diluted -as Charles describes) and Quaternary Ammonium are each effective at killing viruses.
Please note that Vinegar, ammonia, tea tree oil, etc are NOT. This is not a moment to be concerned about using ‘natural’ or homemade products- while we remain under threat of Coronavirus it is very important to use what works.
Please note that any surface must be CLEANED first before a disinfectant will be able to work. It is also very important to leave the disinfectant on the surface for as long as directions indicate, or for 10 minutes if using a product that does not have specific directions for disinfecting surfaces (ie alcohol, hydrogen peroxide.). Leaving the product to air dry on the surface is also effective. If you are concerned about having these disinfectants on surfaces you may rinse AFTER the appropriate dwell time, though that is not necessary.
Stay safe!
Tony A. (March 26, 2020 10:19 AM)
I just dug up a paper by Shirai et al. (DOI: 10.1292/jvms.62.85) which reports the effectiveness of various disinfectants against a selection of viruses. The findings suggest that quaternary ammonium salts are very effective against 'enveloped' viruses (corona is an enveloped virus) at even quite low concentrations. They give an example of an enveloped virus's destruction at a 1,000x dilution of a 10% quat! This corresponds to a 0.01% solution. So this is encouraging with respect to household cleaners that indicate something like even a 0.1% - 0.2% quaternary ammonium salt on the label. But make sure it's on the label, and let the spray sit a while.
Debora (March 26, 2020 8:31 AM)
Can I use Oxine (without activator)cleaner, typically used for chicken coop cleaning ?
Tony A. (March 26, 2020 10:04 AM)
I took a look at an oxine manufacturer's website. Apparently, addition of the "activator" leads to active chlorine species, which are microbiocidal. they indicate that chlorine dioxide is generated; that's what was used to kill anthrax spores in the Capitol after 9/11. So I'd say that without the activator the 'Oxine' may not be very effective.
shabee (March 26, 2020 12:25 PM)
As a precaution to germs in your place or dwelling,I would suggest buying yourself a few plants for oxygen and use a vacuum to help rid your home of nasty air particles by placing the body of the vac outside of your place and use the air nozzle to suck out pathogens from each room individually and simultaniously by placing the nozzle in a window and making it so only the nozzle allows for your air to be sucked through the vacuum.I would say for 20 to 30 minutes at a time throughout the day or night to reduce the effects of germs piling up in your place.

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