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Why soap works so well on most viruses
- dsfyu404ed 7y agoTL:DR Soap (and solvents, and alcohols for that matter) reacts with (and therefore breaks down) the types of molecules that make up oils and fats and the viruses in question are held together by fats.
- undersuit 7y agoThe ability for soaps to clean hinges on the same physical manifestation that keep creates hollow cells for life: https://en.wikipedia.org/wiki/Micelle https://en.wikipedia.org/wiki/Micelle
- dsfyu404ed 7y agoDepends on if your definition of clean is to render the contaminant inert (which is going to basically always involve some sort of chemical reaction) or to just move it elsewhere. If you want to wash the problem down the drain then making large clumps out of the offending molecules helps. If you want to actually alter the offending molecules then you'll probably not want something that makes clumps. This is why doctor's wash their hands while janitors wipe down surfaces with disinfectants.
- amluto 7y agoSoap does not generally react with molecules in dirt or virus, not does it break them down. Soap interacts with the molecules in a way that pulls them apart from each other. All the original virus molecules are intact when they get soapy — they’re just no longer assembled into a functional virus.
- leemailll 7y agoDetergents always work, unless organisms have a thick layer of stuff other than lipids just like human body. Btw, protein denaturants also work, such as bleach
- juandazapata 7y agoWashing your hands with bleach is not very convenient.
- adrianmonk 7y agoIt isn't, and it can also be really hard on your skin. If you want to avoid infections, it's probably a good idea not to damage your skin too much. However, bleach could be a good option for cleaning certain surfaces. For example, countertops, hard floors, and bathrooms. I think restaurants also use it to clean tables and maybe in their kitchens. Since it's getting harder to obtain certain supplies, it's good to know all of your alternatives.
- chungus_khan 7y agoIt's an essential cleaning supply for that sort of thing. Another important point is that if you need something particularly sterile (well beyond what is needed for everyday applications), pressure cookers are essentially a home version of an autoclave, and many of the stronger ones are actually pretty decent at it. Be careful of course though.
- leemailll 7y agoOf course not, it’s used for other stuff. Read the abstract of this paper: https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v1.full.pdf https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v... You will understand washing hand is not enough, also need to sanitize stuff bringing into the house
- pazimzadeh 7y agoBleach is not a detergent. Soap is a detergent.
- tomerbd 7y agoso this explains why 20 seconds, if anyone would explain that at the first place and not just say out of the air wash for 20 seconds I would remember the motivation and understand and do that otherwise I forget what I do not understand. So typical of the shallow news not to explain.
- wool_gather 7y agoSome people, like you and I, do better with the explanation. Some people, like my grandma, get bored about a syllable and a half into the explanation and just want to hear the rule. I agree that both should be accommodated, but I suspect that the large majority case is people who are okay with the high-level presentation.
- me_me_me 7y agoThat is same with anything else you suppose to do but not explained why. The moment I know good reason for why I should be doing something, my resistance to doing so drops to near zero. But most people/authorities only parrot the thing we should be doing, mostly because they don't really understand why.
- pwg 7y agoSome people simply want to be told "what" to do. They don't care about "why". Others wish to understand "why" they are being told to do "that". These folks are typically on the science/engineering side of the spectrum. Unfortunately, the "tell me what" population group size seems to widely outnumber the "tell me why" population group size, so most "reports/directives" from authority accommodate only the "tell me what" group, leaving those of us in the "why" category wondering "ok.... and just 'why' do you want me to do that?"
- Tomte 7y ago> so this explains why 20 seconds Where? I've read the thread three times now and I still have missed the part about 20 seconds. Why not 10 or 30?
- wizzwizz4 7y ago
- oxymoran 7y agoNot that it particularly matters because it sounds like all soap is pretty effective, but I wonder if a grease fighting dish soap would be the most effective of all. Don’t mind me, I’ll just be doing dishes for the next few months.
- undersuit 7y agoSoaps are salts from fats and metals, you could run a panel on lithium grease(actually a soap), sodium and potassium soaps, and maybe something crazy like calcium. Just don't use your hands as the substrate for the experiment.
- stronglikedan 7y agoAlternate soaps to avoid dry hands, since dish soap will strip the oils. Tangentially, if you are handling raw chicken, and then try to use antibacterial soap, it cannot penetrate the grease from the chicken. The trick is to use dish soap first, followed by a second wash with antibacterial soap.
- phonypc 7y agoSkip the second wash. Antibacterial soap is worthless at best and potentially harmful.
- mindcrime 7y agoNot sure exactly how it plays out with the virus killing aspect, but things like Dawn dish detergent contain a pretty effective surfactant. Enough so that, back in my firefighting days, we used that stuff as a "poor man's class A foam." Especially on brush fires.
- Analemma_ 7y agoI've always heard a different explanation from the one in the article: that the soap isn't actually killing many viruses or bacterial cells, but rather just getting them off your hands and down the drain so you're less likely to infect yourself when you inevitably touch your face (I assume I'm not the only one who has been discovering this week just how hard it is to not touch your face). Is that not correct?
- class4behavior 7y agoI'm assuming he's talking about toilet soap, not liquid soap. Both are surfactants, but I suppose, still behave a bit differently. >Consequently, many antibacterial products are basically just an expensive version of soap in terms of how they act on viruses. In that case, this part would be wrong. You use up toilet soap a lot faster than liquid soap, especially if the dosages of the liquid are managed efficiently.
- jplayer01 7y ago> I'm assuming he's talking about toilet soap, not liquid soap. ... what's toilet soap and how does it differ from liquid soap?
- class4behavior 7y agohttps://en.wikipedia.org/wiki/Soap https://en.wikipedia.org/wiki/Soap
- buckminster 7y agoEdit: this is nonsense. See comment below. That says Toilet Soap is any soap used domestically for cleaning. So liquid soap is toilet soap. What do you mean by it?
- class4behavior 7y agoYou didn't even read through the table of contents, nor the initial summary. Both soaps have their own, named subsection, while in the abstract you'll find a succinct explanation which will make sense once you've read that liquid soap is a detergent. >Soap is created by mixing fats and oils with a base, as opposed to detergent which is created by combining chemical compounds in a mixer.
- buckminster 7y agoSorry, the article is broken. I don't see a toc on mobile and the section on liquid soap has been misplaced at the end of the history section. Thanks for the clarification.
- Anthony-G 7y ago> The soap dissolves the fat membrane and the virus falls apart like a house of cards and "dies", or rather, we should say it becomes inactive as viruses aren’t really alive. I always presumed that viruses, similar to other microorganisms, are alive. Until reading the above quote, I had never considered the idea there was any question about this. I was intrigued by the concept that they many not really be alive so looked up the Wikipedia article [1] which says that > Viruses are considered by some to be a life form, because they carry genetic material, reproduce, and evolve through natural selection, although they lack key characteristics (such as cell structure) that are generally considered necessary to count as life. Because they possess some but not all such qualities, viruses have been described as "organisms at the edge of life", and as replicators. One of the Wikipedia references is Are viruses alive? The replicator paradigm sheds decisive light on an old but misguided question [2] which looks at different replication mechanisms as a continuum rather than a simple “life vs non-life” dichotomy. [1] https://en.wikipedia.org/wiki/Virus https://en.wikipedia.org/wiki/Virus [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5406846/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5406846/
- m_eiman 7y agoThey're like memes, I suppose. Cannot live on their own, but replicate like mad when the circumstances are right.
- dnautics 7y agoThe ontology on those concepts goes in the other direction.
- jacobush 7y agoI don't understand. :)
- captain_crabs 7y agoA kind of concerning thought: who's to say there aren't higher-level versions of this same concept playing out? Say we figure out the nature of consciousness and are able to effectively interact with it's "thinginess." Then we find: there are things in our universe that're semi-conscious, but feed and replicate on/inside/with the consciousness of others and are incapable of existing on their own.
- melling 7y agoReading through the thread on Twitter, someone mentioned UV light is very effective in killing viruses. is this true?
- wyxuan 7y agoWashing hands is always the best option. UV might work but you probably would have to do it for a long time and it wouldn't be as effective as soap
- robjan 7y agoIt would also potentially burn your hands.
- nicoburns 7y agoYeah, not a good idea for hands! It can be good for disinfecting inanimate objects though.
- SAI_Peregrinus 7y agoIt needs to be a UVC disinfectant bulb/source though, so massive cancer risk increase (and VERY bad for your eyes).
- nojvek 7y agoCurious why UV is bad for eyes and skin ? The energy kills cells ?
- SAI_Peregrinus 7y agoIt's UVC, so it's ionizing radiation. The sort you put on sunscreen and wear UV-blocking sunglasses to keep from getting skin cancer because of.
- gargs 7y agoThe author wrote an article for Guardian - https://www.theguardian.com/commentisfree/2020/mar/12/science-soap-kills-coronavirus-alcohol-based-disinfectants https://www.theguardian.com/commentisfree/2020/mar/12/scienc...
- scoutt 7y agoI always wondered why surgeons wash their hands using soap (with extreme attention) before operating and not with disinfectants/alcohol/etc.
- jfarlow 7y agoThe other way to think about it is the difference between 'clean' and 'sterile'; having no influential chemicals present (clean), and having no living units capable of replication present (sterile). They are actually different concepts that are caught up in the generic concept of 'clean'. A surface full of massacred microorganisms might be 'sterile' - nothing there can support life, even if given sugar, water, energy, etc. But it's also certainly not clean. If any of the debris from those dead microorganisms could trigger your immune system, were poisonous, or were chemically active they could alter the outcome of a chemistry experiment or trigger an immune response. Disinfectants by definition kill organisms, but don't remove the constituent components of the organisms from the area. Bleach & alcohol in high concentrations (but not pure!) will also destroy most any organisms (but will not in itself remove the debris of those dead organisms). Soaps will link chemicals and molecules to water that is flowed over them, and will remove all of those constituent components along with the water. And if the soap is strong enough, it will also dissolve and destroy smaller organisms in the process. A surface washed with soap will no longer have any debris on it.
- SubiculumCode 7y agoThe use of twitter as a blogging app boggles my mind.
- AgloeDreams 7y agoWhy not? It has millions and millions of users, is incredibly easy to share and propagate info, linking is common and easy to understand. The format basically requires concise summaries prior to longform content so you know what you are getting into. You go where the people are.
- rout39574 7y agoBecause it's a terribly distracting method for presenting
- rout39574 7y agoIdeas of any depth or nuance. This exacerbates an already-problematic tendency towards trivialization on our communications.
- JohnJamesRambo 7y agoI see what you did there and I like it.
- ASalazarMX 7y agoI missed the 1/9, 2/9 and the prescience of counting how many tweets your thread will take.
- thisistheend123 7y agoWell the number of people you can reach with Twitter seems to be the main reason.
- throw7 7y agoThis is fascinating and great information for a layman like myself. Especially how the virus uses the cell's machinery to create the virus' own components (rna/lipids/protein) which then self-assemble. incredible.
- mothsonasloth 7y agoDoes anyone have any advice about using REST or RPC against viruses?
- abainbridge 7y agoI thought it was cells that had a bi-lipid membrane and that viruses had a capsid instead (made of proteins). Wikipedia says "Some viruses are enveloped, meaning that the capsid is coated with a lipid membrane" - https://en.wikipedia.org/wiki/Capsid https://en.wikipedia.org/wiki/Capsid I find the article confusing: 1. Why does removing the lipid layer destroy the virus if most viruses don't have one in the first place? 2. How can soap be effective against "most viruses" (as the article claims) if only "some viruses" (as wikipedia claims) have a lipid layer? 3. Why doesn't TFA mention the capsid at all? I would have thought it should be on the diagram at least. Edit: A simpler explanation that doesn't have these problems and agrees with all the facts I know is that soap destroys proteins, which is what viruses are made out of. See https://www.quora.com/How-do-detergents-denature-proteins https://www.quora.com/How-do-detergents-denature-proteins
- escape_goat 7y agoYou're reasoning from first principles in contradiction of statements of scientific fact that are being communicated to you, however imperfectly. Resolving the contradictions in your own understanding does not constitute a proof. The simplest explanation is that you do not yet correctly understand and that you need further information.
- light_hue_1 7y agoThe point of science communication isn't stamp collecting random disconnected facts. It's to give people mental models that they can use to answer questions. If this information is so half-baked and imperfect that you can't make a basic inference from it, then it's not good science communication.
- RobertRoberts 7y agoYou sound well reasoned, but are not countering or answering his questions with anything of substance.
- escape_goat 7y ago
- smcameron 7y agoI wonder if some soaps are better than others at destroying the virus. Dawn is famously good at cutting grease, used for cleaning up oil spills off birds, etc. I wonder if it's also better than other soaps at destroying the lipid layer of the virus, or if something like Lava or GoJo would be even better.
- cat199 7y ago> I wonder if some soaps are better than others at destroying the virus. not in any related field, but from what I understand the more basic ph the soap the better, modulo additional added enzymes and chemicals
- twic 7y agoShampoo might be best. Most shampoos contain sodium lauryl sulphate, also known as sodium dodecyl sulphate, which is the gold standard for destructive protein-unravelling detergents in laboratory work. Might!
- isbwkisbakadqv 7y agoMy sense is that all soaps are the same from a chemistry/physics perspective. But of course they could be in different concentrations. Maybe Dawn has more amphipathic molecules per liter aka is more concentrated?
- toufka 7y agoThere are 'sufficient' soaps, 'dilute' soaps, and 'specific' soaps. Most soaps are some concentration of SDS/SLS - with various additives to make it smell good, be nicer on your skin, but are otherwise the same, or very similar from an active ingredient perspective. There are concentrated and dilute versions of those soaps. Then there are soaps (like fancy laundry detergents) that are supplemented with various enzymes to specifically target certain kinds of contaminants commonly found in clothes.
- seapunk 7y agoDupe: https://news.ycombinator.com/item?id=22517397 https://news.ycombinator.com/item?id=22517397 Original source: https://twitter.com/PalliThordarson/status/1236549305189597189 https://twitter.com/PalliThordarson/status/12365493051895971...
- RobertRoberts 7y agoYears ago the University of Oregon did research on bacteria and hand washing. Their finding? It's not soap, it's scrubbing in water. Scrubbing hands under water did all the work. Neither anti-bacterial agents or soap had almost any effects at all. I imagine it's not unlike why a stream is safe to drink but a non-moving puddle is not.
- jeffdavis 7y agoThis article is specifically about viruses, not bacteria. It claims specifically that water alone is not effective against viruses like COVID-19, because they stick to the skin too strongly. It also claims that soap and water together are very effective by ripping the virus apart chemically. Additionally, streams are not generally safe to drink from, despite how pristine they may look[1]. [1] https://www.cdc.gov/healthywater/drinking/travel/index.html https://www.cdc.gov/healthywater/drinking/travel/index.html
- RobertRoberts 7y agoHow is no one is worried about viruses in moving water vs a puddle? (I've learned a lot about survival over decades, you can't tell me this is new information) Just like the panic around COVID-19. China, who has more infections and more deaths than anywhere else combined, is already calming down. Yet the rest of the world is just starting in full panic mode. Some people (medical leaders and scientists, not nut cases) are 100% convinced we should panic. This is not rational. We have _scientific_ proof that COVID-19 is not a big deal. Yet here we are.
- triceratops 7y ago> We have _scientific_ proof that COVID-19 is not a big deal. Are you one of those people who think Y2K was hyped up too? China is calming down because of a tremendous amount of hard work, and some draconian restrictions on personal freedoms. The virus didn't just die down by itself. We shouldn't panic. But we should also not be calling it nothing. On a meta-level, this is why societies don't value prevention. And why firefighters who pull people out of wrecked cars are considered heroes, but Nils Bohlin, the inventor of the 3-point seatbelt, usually is not (I think they're both heroes, in different ways). Because we have people who deny there may problem in the future, and then after it's prevented through the application of a ton of someone else's effort and ingenuity say "So it didn't turn out all that bad after all. See? I told you."
- Leary 7y agoI have been washing my hands with the hottest temperature my skin could handle given it is plausible that heat would inactive more of the viruses. I have read studies saying this doesn't help. The skin on the back of my hand is becoming irritated, i am applying lotion.
- gibbonsrcool 7y agoWater temperature has to be about 60-65C and be applied for a period of minutes (longer that bacteria) to harm viruses. Max water heater temperature is about 48C. You're only damaging your skin which will make it more susceptible to pathogens. Source WHO: https://www.who.int/water_sanitation_health/dwq/Boiling_water_01_15.pdf https://www.who.int/water_sanitation_health/dwq/Boiling_wate...
- nitrogen 7y agoAt least some water heaters can be set a fair bit higher than 122F/50C (good for dishwashers), but then you'd really want to use a temperature mixing valve for anything you might touch directly.
- DanBC 7y agoCDC have a nice document called "When is clean too clean?" https://wwwnc.cdc.gov/eid/article/7/2/70-0225_article https://wwwnc.cdc.gov/eid/article/7/2/70-0225_article It explains the problems caused by skin irritation. You only need warm water to wash your hands. (But you need very hot water in the pipes, especially with long plumbing runs, to kill things like legionella).
- filleduchaos 7y ago...I admit that this is likely too personal a question, but my curiosity can't resist. Do you just...not use lotion normally?
- rrauenza 7y agoWhat I'd like to understand is why viruses are less prevalent in the summer due to more humid air, but yet they can exist in the moist body and spread from moist spray from coughs / sneezes. I haven't been able to phrase the question just right to find the answer to what seems like a conflict. I think the spray is just a method of transmission with the virus "hoping" to dry out quickly on a dry surface before it falls apart. But inside the body?
- 3JPLW 7y agoThis paper confirms the finding (google search: droplet transmission "winter"). They're uncertain of the mechanistic cause, though. They summarize: > Cold and/or dry conditions impact the stability of influenza virus particles, the innate defense of host nasal epithelia, and the production of infectious bioaerosols. Each of these effects contributes a plausible explanation for the impact of [relative humidity] and temperature on respiratory droplet transmission, and more than one mechanism most likely contributes to the observed transmission outcomes. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4097773/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4097773/
- xenospn 7y agoI was under the impression it was heat, not humidity, that caused viruses to become less effective.
- pas 7y agoI don't know the impact factor of these journals, and a bit too lazy to look up, but it's probably a very complex problem, otherwise it'd be settled by now. A 2018 study claims that it's independent of humidity, but their 2019 one seems to show a trend with absolute humidity. [2018] https://www.health24.com/Medical/Flu/News/humidity-doesnt-slow-down-spread-of-flu-virus-20180813 https://www.health24.com/Medical/Flu/News/humidity-doesnt-sl... https://academic.oup.com/jid/article/218/5/739/5025997 https://academic.oup.com/jid/article/218/5/739/5025997 [2019] https://royalsocietypublishing.org/doi/full/10.1098/rsif.2018.0298 https://royalsocietypublishing.org/doi/full/10.1098/rsif.201...
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- jasonmp85 7y agoWhy is this 25 tweets when something like “lipid envelope” would suffice?
- melenaos 7y agoDoes anyone knows if liquid soap is as effective as soap bars? I have this argument over and over agin with my wife.
- bittercynic 7y agoIs there room at the sink for a pump and a bar?
- flr03 7y agoInteresting! My girlfriend told me off recently after I washed my hands with a soap bar because we ran out of liquid hand wash. For me it's the reaction of water and soap all together that matters, this happens regardless of the state of the soap (foam, hard, liquid...).
- toufka 7y agoFoam ≠ good soap. Almost all commercial soaps are decent soaps (for the purpose of killing organisms/viruses) that vary only in how nice they treat your hands, and how they smell. Consumer soaps add foaming agents specifically so people think "they're working" - the foam does nothing. Bar soap is still soap, and works' fine - it's just less convenient to use. Go find an industrial or laboratory soap - that stuff is pure SDS/SLS, flows like olive oil, will remove the top few layers of your skin, and doesn't foam at all.
- uoaei 7y agoOnce the soap molecules are dispersed into the water, it acts just like liquid hand soap.
- 29athrowaway 7y agoSmart people of HN: what are your thoughts on the antiviral properties of flavonoids like kaempferol?
- topaz0 7y ago*hydrophobic