Thanks!
The reason I asked was before this virus became a threat, I was not making the distinction between the terms anti-virus, anti-bacterial, and antiseptic.
Purell is listed as a hand sanitizer, is 70% alcohol, and advertises that it will kill corona virus in 60 seconds. and is sold out every where.
In the grocery store the other day we found hand soaps and washes listed as anti-bacteria, such as Dial Complete Foaming Anti-bacterial Hand wash with Benzalkonium Chloride which I see you listed above, which in one article I read said it was less effective against viruses.
And for soap, I assume it depends on the soap, but my impression is that soap functions to wash the virus off your hands, but may not in itself kill the virus.
Probably more information than you wanted to know hahah.
[Quick note- I just checked, the FDA’s ban on the 28 antiseptic agents goes into effect April 2020. Therefore products with those agents technically still might exist, though reportedly the ban would only impact 3% of sales. So the product you mentioned could contain something other than alcohol or Benzalkonium Chloride (BZK).
Confusion especially comes into play when you have products marked by by brands typically associated with alcohol-based sanitizers. For example, the name “Purell” is associated with a alcohol-based gel hand sanitizer. Most “Purell Hand Sanitizing Wipes” however contain BZK rather than ethyl alcohol... BUT Purell also offers another product
also called “Purell Hand Sanitizing Wipes” that instead use alcohol. You really have to read the fine print.
As I mentioned in the COVID-19 Information Thread, despite the CDC’s recommendation to use alcohol-based hand sanitizers, alcohol-free products have also sold out. As you mentioned, Benzalkonium Chloride (BZK) has very limited effectiveness against viruses and unlike alcohol... and also requires a very long residence time to reach its maximum effect.
Antibacterial soaps fall into a different product category called “Antiseptic Hand Washes” and we’re part of the FDA’s 2016 interest in investigating hand sanitizer ingredients. You may remember the hubbub of Triclosan being banned from soap- this came out of the same 2016 investigation/regulation. As it stands now, antibacterial consumer hand soap now limits available antiseptic agents to benzalkonium chloride, benzethonium chloride and chloroxylenol.
You’re correct that soap primarily is intended to wash away pathogens. But it’s not just the mechanical movement of scrubbing and water flow. I‘ll try not to bore you with my esoteric appreciation of the chemical properties of water and emulsifying agents and the science behind them, but it’s actually pretty cool phenomenon.
Soap’s emulsifying agents encapsulate lipophilic materials. Typically people only think of removing oils or dirt when it comes to soap’s function. But molecules, particles, and pathogens, etc can be lipophilic. Coronaviruses possess an envelope (exterior structure) composed of various types of lipids and proteins making it highly lipophilic entity. Emulsifiers are basically molecules that are lipophilic/hydrophobic at one end and hydrophilic/lipophobic at the other.
In the presence of water, the lipophilic ends of the emulsifier are drawn to the virus’s envelope. The hydrophilic ends are drawn to the water molecules. Therefore emulsifier molecules naturally encapsulate the virus (and oils, dirt particles, etc), draw them away from the skin (skin is also lipophilic), and force them to be suspended in the water and washed away.
A secondary benefit: Because skin is lipophillic, emulsifying agents and other components of soap are attracted to skin cells. Therefore people generally are forced to wash their hands longer to get the soap off, which means more time for pathogens to be removed than might have occurred without soap.
There is a bit of controversy as to the need for antiseptic agents in soaps and how much benefit they actually provide. Currently the CDC says antimicrobial soap is unnecessary for general use by the public. Antimicrobial soap is recommended for healthcare settings- but there are some reasons for that but I’ve already been too tangential.
In the context of COVID-19, the underlying pathogen is obviously a virus and viruses aren’t particularly susceptible antimicrobial soaps, typically most effective against bacteria.
As I’ve mentioned elsewhere, some pathogens are even invulnerable to alcohol. C. Diff is a textbook example- it’s highly contagious and very difficult to kill in or outside a host. Many pathogens when sensing an unfavorable environment can create spores to essentially hibernate until favorable conditions arise to protect themselves. Such spores can be incredibly resilient- unaffected by heat, pH, temperature, etc and can stay dormant for longer than we’ve been able to test them.
So killing the pathogen is not the be-all-end-all of protection from infection. In fact, even in antibiotic treatments many medications work through a bacteriostatic rather than bacteriocidal mechanism (preventing further bacterial growth rather than outright killing all the bacteria). If you’ve ever taken Azithromycin (aka a “Z-Pak”) the medication doesn’t really kill the infection as much as prevents bacterial growth and reproduction- effectively your immune system kills the bacteria.
Not to go off on another tangent, but there have been some isolated examples of pathogens displaying “acquired resistance” (developed, learned) to general antiseptics/disinfectants like alcohol and BZK (ie alcohol resistant staph/MRSA). This is not to be confused with “intrinsic resistance” (normal, expected - ie C. diff to alcohol)]. This was part of the impetus for the FDA to review how such products are being used. That said, these events are not common and isolated. Because of their mechanism of action, development acquired resistance to alcohol and BZK is far more difficult than traditional antibiotic and antiviral pharmaceuticals.
Resistance to alcohol-based antiseptics is probably not something we really need to worry about with COVID-19. Mutations and resistance however will always pose a threat to whatever antiviral treatments and vaccines we develop, but mitigate some of those risks.
As the CDC guidelines suggest, hand washing
with soap is essential- antibacterial/microbial/septic or not. I wouldn’t expect much if any benefit in using antibacterial/antimicrobial soap in the context of COVID-19 protection. But I suppose people can decide for themselves what they’re most comfortable with.
(Note: when it comes to body soaps and showering, there’s a good argument against not using soap with antibacterial properties, but that’s another discussion).
