Why soap works so well on most viruses | Hacker News Reader

Why soap works so well on most viruses

threadreaderapp.com

378 pointsjxub198 comments

I 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

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

1. Viruses that don't have an envelope have evolved to survive without the envelope. Viruses that do have an envelope haven't. Are you confused that removing a crab's exoskeleton kills it, given that there are lots of animals that don't have exoskeletons?

2. This is probably just sloppy usage of "some" and "most". That said, i think enveloped viruses are overrepresented amongst viruses that cause serious disease in humans, because the envelope helps them evade the immune system.

3. Some viruses don't have a capsid [1]! Coronaviruses do, though, so that's just missing from that diagram.

4. Surfactants like soaps do disrupt protein, but typically not as effectively as they disrupt lipid bilayers. There are numerous techniques in biochemistry and cell biology that depend on this fact - permeabilising cells for immunocytochemistry, or preparing membrane proteins for crystallisation, for example. You have to boil proteins in powerful detergents to be sure of denaturing them.

[1] http://www.virology.ws/2010/09/23/a-new-type-of-enveloped-vi...

The article is about "most" viruses, and according to him, "most" viruses don't have a lipid layer, so I think it's a fair criticism, unless what he said is factually incorrect.

You'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.

The 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.

You sound well reasoned, but are not countering or answering his questions with anything of substance.

He is taking his current understanding and coming to the conclusion that the mechanism by which soap renders viruses inactive is 'actually' because it destroys proteins. I am pointing out that this exercise is futile and does not result in useful knowledge.

If a domain expert says something that does not make sense to you, there is a small chance that the domain expert is wrong, but it is more likely that what the domain expert is saying is correct and your own knowledge is incomplete.

Maybe lay people might also share this person's misconceptions/concerns, so it's in the interest of the common person for a subject matter expert to provide them with some citations or supplementary reading (where to go to learn more on your own time).

Critical thinking and asking questions should be welcome and reinforced in the public sphere to improve our collective intelligence and buy-in for hand washing, proper respiratory etiquette, etc. towards containing and eradicating this pandemic, among a multitude of many other greater societal good reasons.

Sure. You will notice that I was not criticizing anyone for thinking critically or asking questions. I was pointing out something that I still believe to be a failure of critical thinking, and that we could know a priori that this was a bad way of reasoning about things without reference to prior knowledge.

I notice that my opinion is unpopular with people interested in this topic, and I'm certainly familiar with being wrong about things, but in my opinion going from "an expert told me that envelope viruses are deactivated when soap destroys the envelope" to "the real reason that soap deactivates viruses is because it destroys proteins" on the basis of the semantics of a line from a Wikipedia entry is categorically problematic on the face of it.

Most of us here are in the habit of relying on our ability to discover knowledge by reasoning about limited information. It is how one solves puzzles. It is not how one learns things about the world. Believing that we know something which we don't know is dangerous in this situation. Convincing others that we know something we don't know is also dangerous.

What I am doing right here is exactly attempting to improve our collective intelligence. I am certainly not dissuading anyone from washing their hands. I am encouraging people to second-guess themselves before they second-guess others.

> 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

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5406846/

As a biochemist, i think it's absolutely clear that viruses are not alive, because they don't do anything. No metabolism, no signalling, no changes in structure, no use of energy or materials. They just float about! It's only when they encounter a cell that anything happens, and then it's mostly the cell's machinery doing it.

If i was a molecular biologist, i would probably think it was absolutely clear that viruses are alive, because they contain a genome, and proteins encoded by the genome, and they use the proteins to make more copies of the genome. What else is life?

I'm of the opinion that whether something is alive or not is arbitrary, and depends on your definition. Humans just came up with the word to describe a class of things.

You could define biological life in a way that includes or excludes viruses, I would suggest, and be right either way.

(Also if a biological virus is alive, is a computer virus alive? It's self-replicating and has DNA in the form of code.)

I have three tests for what's alive and what's not. Those are from most fundamental to least.

Fundamentally life is a thermodynamic machine. Takes energy and converts a portion of it to 'work'.

Under homeostatic control. There are feedback systems that maintain the integrity of the organism.

In theory has a way of reproducing. This more applies to the species as a whole. Since individuals incapable of reproducing are none the less alive.

Viruses only meet the last and weaker criteria in my book.

The virus isn't the lifeform. The virus is just one component needed for the lifeform to exist and reproduce. The lifeform is the infection.

So the lifeform is the disease? I think assigning "lifeform" status to an illness is not really helpful.

Viruses are just replicators. Grey/Green/Brown/Bio goo. They are just dumb machines made by brute-forcing (fuzzing) more complex machines' immune systems.

Viruses might be a different branch on the RNA-replicator tree. Probably when the first replicators started some found - again via brute-forced mutations - that there are some replicators that they can take advantage of to replicate themselves.

And it just seems that closing this security hole is neigh impossible as long as we don't start to seriously tinker with that low level of "life" (eg. cellular machinery, transport, nucleus, messenger and transcription security).

> Viruses might be a different branch on the RNA-replicator tree. Probably when the first replicators started some found - again via brute-forced mutations - that there are some replicators that they can take advantage of to replicate themselves.

One of the dominant theories for how eukaryotic organisms evolved (and by extension multicellular life) is by incorporating viruses and other prokaryotes internally and there's evidence a variety of viruses permanently entered the gene pool of several animals that were theoretically naturally selected for. It's less a branch and more a mobius rat's nest.

> They are just dumb machines made by brute-forcing (fuzzing)

But that's no different how the rest of biology works. A parasite like Giardia is relatively just a dumb machine brute forcing itself through my immune system.

No, no, of course not. You're right. The same exploitation of complexity-difference can be observed all the way up the hierarchy. But that doesn't make it "living". (Or if you define liveness on a spectrum, like we sort of do with sentience/consciousness, then viruses are alive like rust is conscious.)

It's very likely an invariant of complexity. Trade offs (and friendly turtles) all the way. And of course evolution doesn't optimize for QALY at all. So it's not surprising that it hasn't really spent much resources on closing the gap. And now we try to do it because we do find it a better goal than "just" thriving in every imaginable niche on whatever complexity it's possible. (We want to maintain our complexity plus occupy more niches.)

I think you are narrowing on one phrase and ignoring all of the context around it, which is generally not very conducive to understanding a speaker's point.

Physically, what constitutes the infection?

The viral RNA, whatever the viral RNA is producing, and whatever components of the cell are directly working on the new viruses. There are intracellular parasites, a viral infection is just an intracellular parasite... that doesn't have a definite boundary like a cell membrane.

interesting point of view

I think I came around to that way of thinking after reading about multi-part viruses: https://www.the-scientist.com/the-nutshell/newly-discovered-...

See also adeno-associated viruses, which can only replicate in a cell which has been infected by another virus:

https://en.wikipedia.org/wiki/Adeno-associated_virus#Infecti...

This is the key point I think: viruses have no metabolism. There is no stable energy transfer with their environment. Their genomic feedback does not promote metabolic growth (ie greater energy transmission rates).

A virus is not able to reproduce itself on its own. Because of that I don't consider virus as a life form. I'm biologist, in case it matters.

I cannot reproduce on my own, I need a mate and food and water and air to properly reproduce, that is most life is dependent on its environment to survive including other organisms depending on their needs.

A virus needs a host like any parasite, without the host many parasites would not be able to reproduce.

On a technical level, whether something can reproduce by itself or not is defined by whether they use their own chemical machinery to produce the offspring, such as when a cell divides itself or organisms produce their own gametes.

To be pedantic, all you need is at most two (or three, maybe?) of the right gender to reproduce in a vacuum (metaphorically) to make it a living organism. A virus can't reproduce with another virus that way because it can't do anything on its own other than float around waiting for a host, no matter how many strains you mix it with. The host does the actual reproducing for the virus.

Indeed; the virus being reproduced is just a side effect of the cell making reproducing actions.

Cells can repeatedly produce certain proteins. For instance, a silkworm can spin out a thread of silk. That doesn't meant that molecules of silk are alive because they are reproducing.

Silk doesn't go on and reproduce through another silk worm once made its complete.

Any parasite that requires its host for reproduction could be said to be a byproduct of the host continuing its biological functions usually at the expense of the host.

Nature draws no clear lines, humans apply taxonomy, any line we draw about what is alive and what isn't will be arbitrary.

My opinion is a virus is alive as it core process is based on how all life on earth operates through DNA/RNA. That is my arbitrary line, a distinct self contained genetic code that continues to replicate and evolve is alive. If that code can no longer continue replicating successfully it is dead.

A virus by itself does not perform any biological functions whatsoever; it just alters the course of events in a host cell.

Potassium cyanide can alter what happens in a cell; that doesn't mean potassium cyanide is alive.

Humans aren't either. We need food and water and a hospitable environment to get to a point where we can do that.

I think that's a pretty good analogy. Viruses are just as incapable of being considered life as our chromosomes are, until you give them a support network.

This is a confusion of _can_ and _will_.

Are lichen fungi life forms?

Not unlike prions? which have some qualities of "life" but really can't be considered as such?

I work with some groups trying to build synthetic cells, and honestly there isn’t even a good definition for what a “cell” is or what “life” is in the scientific communities. The best proxy I can come up with, which is universally true on earth, is that life is anything that fully encodes ribosomes and can replicate (there aren’t any discovered exceptions to that yet, though some are close). Very intellectually unsatisfying, but so far factually true for anything generally considered “living”.

Evolution/competition between ribosome encoding and capsid encoding organisms[1] has driven a lot of cool stuff to be developed: for example, bacteria and archaea (+ eukaryotes) gained DNA separately (presumably from viral infection) and retroviruses enables placentas.

[1] https://www.ncbi.nlm.nih.gov/m/pubmed/19845628/

It reminds me of a philosophy class where the goal is to find an accurate and all-capturing definition of what a chair is.

It is tremendously difficult, perhaps impossible.

I just tried to come up with a definition and I feel like I'm almost there but not quite.

A chair is something you can sit on (but you can also sit on a rock)

&& it has a backrest (but the foot of a tree serves as a backrest)

&& it elevates you off the floor (but not all chairs take you above floor level very much)

&& it is manmade.

I believe the correct approach is by looking at purpose, and more importantly primary purpose, rather than try to describe the chair itself.

Eg, a chair is any object whose primary purpose is to sit a single individual

If it's meant to seat multiple people, it's a bench, a sofa, etc, but not a chair

If it's meant to be extra comfortable, it might be a single-seat sofa, but this itself a chair

If it's a rock, but positioned such that it's primary purpose is to sit an individual, such as next to a table, then it's a chair.

And most notably, primary purpose is subjective -- it might be understood as a chair, or as a doorstop, depending on your viewpoint, and what you use it for.

What about stools? I don't consider a stool to be a chair, I consider them two subtypes of seating. If someone told me to grab a chair and gestured to a stool I'd find it very slightly odd.

Fine

To sit an individual at close to, or at, a right angle in regards to their legs

A small rock versus a big rock; Approximating a squat, or standing, is out of bounds

But a stool may consistute a chair when sitting a child

Regardless, I'm mainly talking about the approach to defining it, and that definition by purpose rather than structure is more likely to find a correct definition, not that my example definition is sufficient

> a chair is any object whose primary purpose is to sit a single individual

So is a zabuton[1] a chair?

[1] https://www.dharmacrafts.com/01_zb/zabuton-mat

what if we add: "with one's feet firmly on the ground and legs bent at knee at more or less right angle?"

Highchair.

Now you have to find an accurate and all-capturing definition to all the terms you used (manmade, floor, backrest, ...)

It's a game you cannot win.

Plenty of ergonomic chairs don't have a backrest.

There are also ergo chairs that you "kneel" on instead!

This would classify a Honda Goldwing as a chair, but exclude the Balans kneeling chair.

Also applies to a Sofa

Now I'm doubting if car seats are chairs too...

What is a sofa if not shared chair?

A chair is anything used as a chair. :)

EDIT: Addendum: It may also be worth asking what definition of truth you're using if we're going to be getting into philosophical arguments about what things are: https://en.wikipedia.org/wiki/Truth

And what about an expression like "accounting department chair"?

An accident of the English language; some people would insist on "chairperson" there, and some older people might still insist on "chairman" but that's becoming less and less acceptable over time. As an even better example, there's "fluke":

1. A fish, and a flatworm.

2. The end parts of an anchor.

3. The fins on a whale's tail.

4. A stroke of luck.

The meanings are etymologically distinct (for the most part) and it's only chance they ended up wit the same spelling and pronunciation.

If that's philosophically troublesome, linguistics is not for you.

There’s a bit of leeway here, since that’s the word used in a different sense. But I would say that if you ask someone to “define what a chair is” that the word is being used in one sense only, compared to what happens when you ask someone to “define what ‘chair’ means” which is about the word.

That is, when we refer to a word like “chair” we use quotes, but without the quotes, we can say that an accounting department chair is not a chair.

Alternatively, we could analyze “accounting department chair” as a use of metonymy.

limited namespace conflict? Same word, different abstract concept than the chair under question

I always assumed it came by naming the person who sat in the special seat after the seat itself.

This has a name! It’s called “metonymy.” It’s incredibly common in casual speech and poses unique challenges for natural language processing. https://en.wikipedia.org/wiki/Metonymy

that might be the case but the person himself is not an object to be sat upon (though this may be true metaphorically... hopefully not literally).

“The person that sits in the chair generally used by the head of the accounting department” :)

So the world is… duck typed? :)

That exercise makes me feel like too many people believe that accurate == perfect.

The boundary between "life" and "not life" has some fascinating organisms/structures[0]:

  Virions
  Viroids
  Satellites
  Prions
  Defective interfering particles (DIPs)

I would also add t-RNA[1] to that list. It can almost replicate by itself, and sits right in the middle between "data" (DNA/RNA) and "code" (a small machine that can selectively hold an amino acid)

[0] https://en.wikipedia.org/wiki/Virus_classification#Subviral_...

[1] https://en.wikipedia.org/wiki/Transfer_RNA

Prions are the things of nightmares. Good god, I wish I never read up on them.

They're the strange matter of the biological world :)

>> viruses [...] are alive. Until reading the above quote, I had never considered the idea there was any question about this.

> in the scientific communities

"Is it alive? <long property checklist> Yes/No" is an example of K-12 science education content diverging from science community practice. Both by emphasizing a little used concept, and by being inconsistent with community use.

With bonus points for it being... widely taught; taught as if it were science; an unnecessary hook for learning a set of properties; and an incoherently unfruitful predicate.

I don't know if there's a real name for such? I call them science-education-isms.

The categorization of life and non-life is the first step in taxonomy, which was historically based on long property checklists. I think it may be more the case that advances in biology have changed the science. The emphasis moved from stamp collecting to modelling as we acquired better tools and a deeper understanding of biological processes. Education just got left behind.

Interesting idea. I wonder how one might easily explore it?

Google trends has data to 2004. "living nonliving"[1], aside from being a school-year detector, seems to show a 3x increase in the 2010's?

I'll also link [2], but I don't know what to make of it.

[1] https://trends.google.com/trends/explore?date=all&q=living%2... [2] https://books.google.com/ngrams/graph?content=living+and+non...

I’d love to connect with you. I’ve been developing a discrete time control systems model of the central dogma as a signal processor of environmental EM radiation (eg heat).

So would that younger than a fetus be considered life?

Bacteria are considered life and you kill them by the thousands daily. You meant conscious life?

It is sometimes useful to remember that lines are drawn by the human mind, they are not an inherent property of the universe.

True, but ultimately of no consequence to the discussion in hand. Nothing we say or do is of consequence to the universe, but they matter to us. Ultimately, these lines are drawn for our benefit, not the universe's.

In my highschool biology class (that makes me an expert... right? :) ) The definition of life included self replication and, IIRC, having some sort of metabolism. The reason my biology book classified viruses as not alive is simply because they are incapable of self replication and they don't really have a metabolism to speak of (Old viruses are still infectious).

Wait I can't self replicate...

Virus behave like life in some ways. They're made out of the building blocks of life, and are indeed subject to evolution. But they don't absorb nutrients and don't reproduce themselves. They are created by the cells they infect.

But it's a thin line, and it depends on which definition you want to use.

I have come to view them (from a programer's sense) kinda like functions and stateless services compared to living life which is like classes and other state-y things. It can change classes, it can be mutated and overridden, but does not think or act on its self, it must be interacted with.

Interesting. I also have a programmers model. But in my head the virus is the static artifact, the code. While what’s living is the process interpreting that code.

Or rather SARS-CoV-2 is the nonliving static code. COVID-19 is the “living” process interpreting the code.

Or your DNA is the code, you’re the living process interpreting that code.

My take: DNA (in a suitable environment) is a self-hosted DNA interpreter executing code to regulate its own environment via RNA JIT bytecode compilation. Viruses are… well, viruses.

The CPU, in this analogy, is physics.

If virus are alive, then internet memes are alive. —They reproduce not by themselves but by infecting other organisms -- They evolve / mutate

Come on, we're getting too philosophical. Viruses have genes, internet memes are just ideas.

What difference is there between information stored as proteins in a chains or as bytes on hard drive / neuron configuration in your brain.

We just got used to the DNA=life, but is this a valid assumption?

Some exotic lifeforms could encode their self-defining information on silicium magnetic polarisation, electron spin or whatever. And you would call them life if they were standing and moving in an animal-like way.

Do you know where the word meme comes from?

Of course, and that reinforces their status of imaginary genes.

I didn't read The Selfish Gene, the book that coined the term "meme", but I heard that it mostly explores that analogy, for a much broader definition of meme.

Random analogy - is a flash drive a computer?

Certainly. It does compute and without computation property it will be not possible to store and retrieve information.

A flash drive often contains a microprocessor/microcontroller which could be programmed to do more on its own

I, for one, as a human being whose root ancestors¹ infected planet Earth² which eventually produced me³, am will to use a definition that qualifies viruses as very much alive. ;-)

____

Tangentially related, I sympathize with Earth parasite Musk who wishes for us to infect another cell— err, I mean, planet. Shoosh, Earth, back to sleep, nothing to see here...

____

[1]: I wonder who's the chicken, here. Certainly, the virus is the egg, right? It's all a plan to engineer the actual masters of this universe?

[2]: A long, long time ago...

[3]: Well, the 10% of my weight with my DNA. I feel more like an ecosystem, I am a legion of species, a myriad DNAs, we are millions in those guts. "I" is not even the same "I" when travelling to a different biome: you are what you eat, quite literally, however you want to spin that idea.

EDIT: also a biochemist in a previous life.

If viruses are on the edge of alive, then books and posters might be too, in some sense.

Virus's are "life" without replication machinery. And what is a book but a similar sort of dormant form, without the fertile replication machinery of the [human] mind to remix it and help its ideas fuck with other ideas. This view of viruses and words as life perhaps isn't as wrong as it first sounds, and some linguists on the fringes argue that language is more like a semiotic symbiont that has "moved into" our biology, specifically our neural structures, like a creature moving into an ecological niche and modifying it to suit its purposes. Or as I prefer to think about it: maybe we're already cyborgs straddling structures of biology and semiotics. (See: The Leiden School of Language[1]).

Maybe humans are just the first example of this language portion of our organism starting to venture cautiously outside of our biology, like astronauts exploring outside spaceship corpus ;) Reality might be pretty weird imho, and hard to see for what it truly is.

[1]: https://books.google.ca/books?hl=en&lr=&id=_ind5AbdQaAC&oi=f...

They're like memes, I suppose. Cannot live on their own, but replicate like mad when the circumstances are right.

You've formed a funny circle: the concept of a meme was explained by analogy to a virus when it was introduced. (In The Selfish Gene.)

A 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.

The ontology on those concepts goes in the other direction.

I don't understand. :)

You mean they go viral?

Time for Kurzgesagt (What is life?): https://www.youtube.com/watch?v=QOCaacO8wus

+1 the old homeostasis argument. In that regard viruses are definitely life.

Maybe they actually are vastly superior to us and the hosts are just their air to breathe.

In Icelandic the word for life is "líf", there is also another word "eilíf" which is concatenated from "ei" meaning "not" and "líf" meaning "life". This word means "eternal".

Therefore: The definition of life is "not eternal" (if you assume the law of excluded middle - actually the definition of "eternal" is "not life" :)

The author wrote an article for Guardian - https://www.theguardian.com/commentisfree/2020/mar/12/scienc...

What 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?

This 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/

Heat, humidity and sunlight all reduce infections during summer.

Humidity seems to reduce infection multiple ways.

1. Testing shows that there is less virus particles in air after it has been humidified. Stuff like droplets, dust and micro-particles fall down faster.

2. In dry air viruses may have more direct way into lungs and other tissues when the protective moist layer is evaporating away.

> Testing shows that there is less virus particles in air after it has been humidified. Stuff like droplets, dust and micro-particles fall down faster.

Seems feasible but can you provide a citation? Thanks!

Short answer: we don't know.

"The exact mechanism behind the seasonal nature of influenza outbreaks is unknown."

https://en.wikipedia.org/wiki/Flu_season#Cause

My personal theory is that in places like England in the winter people close the windows and cough at each other hence spreading colds, flus etc. In the summer they open the windows, go outside, the cough outputs blow away. I was recently in Bali and Singapore and noticed no colds in Bali where everything is outdoor and transport is mostly scooters and a lot in Singapore where everyone sits in aircon boxes - offices, busses etc. Also there's a fair bit of coronavirus in Singapore and not much it seems in Bali in spite of Bali having many Chinese tourists.

I was under the impression it was heat, not humidity, that caused viruses to become less effective.

I 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-sl...

https://academic.oup.com/jid/article/218/5/739/5025997

[2019] https://royalsocietypublishing.org/doi/full/10.1098/rsif.201...

It's hotter inside your body on most days of the year, even if you live close to the equator.

Also more humid!

Perhaps the humidity only affects when it's not attached to a host cell?

so 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.

Some 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.

Some 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?"

That 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.

> 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?

Correct... the article does not explicitly mention the 20-second recommendation, which was presumably arrived at by experimentation. But it does explain why such a time-based recommendation might work:

> The skin is quite rough and wrinkly which is why you do need a fair amount of rubbing and soaking to ensure the soap reaches very crook and nanny on the skin surface that could be hiding active viruses.

It's a complex balance between the effectiveness of the behaviour and the willingness of people to perform it. That's the usual reason, anyway.

So long as you're not stripping away layers of skin, I don't see why 30 seconds wouldn't be better.

Sure, but grandparent spoke about an explicit explanation.

I always wondered why surgeons wash their hands using soap (with extreme attention) before operating and not with disinfectants/alcohol/etc.

The 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.

I'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?

I think that's the case with bacteria, and maybe viruses that are put together in a different way. But from what I understand, these particular viruses are particularly vulnerable to soap.

It seems like both effects are happening.

Dupe: https://news.ycombinator.com/item?id=22517397

Original source: https://twitter.com/PalliThordarson/status/12365493051895971...

This 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.

Detergents 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

Washing your hands with bleach is not very convenient.

It 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.

It'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.

Of course not, it’s used for other stuff. Read the abstract of this paper: 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

Bleach is not a detergent. Soap is a detergent.

I 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.

Shampoo 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!

There 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.

My 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?

> 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

Does anyone knows if liquid soap is as effective as soap bars?

I have this argument over and over agin with my wife.

Interesting! 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...).

Foam ≠ 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.

Once the soap molecules are dispersed into the water, it acts just like liquid hand soap.

Is there room at the sink for a pump and a bar?

I 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.

Water 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_wate...

At 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.

CDC have a nice document called "When is clean too clean?" 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).

...I admit that this is likely too personal a question, but my curiosity can't resist. Do you just...not use lotion normally?

Not 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.

Soaps 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.

Not 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.

Alternate 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.

Skip the second wash. Antibacterial soap is worthless at best and potentially harmful.

Does anyone have any advice about using REST or RPC against viruses?

Enough XML can kill anything.

Just return 401. Or 301. Virus will disappear!

Reading through the thread on Twitter, someone mentioned UV light is very effective in killing viruses. is this true?

Washing 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

It would also potentially burn your hands.

Yeah, not a good idea for hands! It can be good for disinfecting inanimate objects though.

It needs to be a UVC disinfectant bulb/source though, so massive cancer risk increase (and VERY bad for your eyes).

Curious why UV is bad for eyes and skin ? The energy kills cells ?

It'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.

Smart people of HN: what are your thoughts on the antiviral properties of flavonoids like kaempferol?

TL: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.

The ability for soaps to clean hinges on the same physical manifestation that keep creates hollow cells for life: https://en.wikipedia.org/wiki/Micelle

Depends 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.

Soap 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.

The use of twitter as a blogging app boggles my mind.

Why 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.

Because it's a terribly distracting method for presenting

Ideas of any depth or nuance. This exacerbates an already-problematic tendency towards trivialization on our communications.

I see what you did there and I like it.

I missed the 1/9, 2/9 and the prescience of counting how many tweets your thread will take.

Well the number of people you can reach with Twitter seems to be the main reason.

*hydrophobic

Why is this 25 tweets when something like “lipid envelope” would suffice?

Years 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.

This 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

How 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.

> 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."

> ...one of those people...

Ad hominem

Proof question: How many rats do you need to test to determine with a high rate of accuracy a disease's CFR?

It was a simple question. And you didn't answer the rest of my post. Are you asserting that China would've had the same outcome if they had done nothing?

We already know how bad it can get. It's be tested and proven under lab-like conditions.

If you want to panic and spread irrational noise, go ahead. There's no point arguing with people that don't want to discuss the science side of things.

> If you want to panic

Can you please explain where I said that? I'm pretty sure I said "We shouldn't panic" (https://news.ycombinator.com/item?id=22559590).

I'll say it again. We shouldn't panic. It is counterproductive. But so is passiveness, inaction, and complacency (such as saying "it's not a big deal" as you did). Facing up to a problem, and dealing with it calmly and resolutely isn't panicking.

> There's no point arguing with people that don't want to discuss the science side of things

I'm not certain what "science" you're talking about here. What "lab-like" conditions? Are you saying containment efforts are unnecessary or unhelpful? I seriously have no idea.

Argue with doctors, data and non-panic induced social media. Bring ur lazy sideways anti-science arguing elsewhere.

One example of many, go argue with them.

https://imgur.com/gallery/mAOTOI8

Seriously, what have I said that was "anti-science"? I'm in full, 100% agreement with the link you posted. "Don't overcrowd hospitals, watch for the symptoms, self-isolate, call doctors before going in, flatten the curve etc." Those are the exact measures that need to be taken.

What I was disputing was your original statement "COVID-19 isn't a big deal." If large portions of the population have to take all these measures to keep this thing under control, it seems like a pretty big deal to me.

At this point I feel like you're just trolling. You aren't responding to anything I've said at all.

Tell this data it's wrong:

https://imgur.com/gallery/FETiDTV

Anti-hysteria from a _doctor_, argue with him:

https://imgur.com/gallery/XN9pvQM

(no point in actually discussing anything with you)

> (no point in actually discussing anything with you)

I feel the same way. Not one thing I've said contradicts anything you've posted. Definitely a troll. Or you took offense at the first thing I said and are determined to ignore literally everything else I wrote.

I'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.

> I'm assuming he's talking about toilet soap, not liquid soap.

... what's toilet soap and how does it differ from liquid soap?

Not OP, but I'm guessing he means soap generally available in a bathroom. (toilet) Which would, of course, include a variety of soaps.

I'm pretty sure they're talking about solid bars of soap.

https://en.wikipedia.org/wiki/Soap

Edit: 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?

You 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.

You're getting it wrong and you're confusing everybody. Detergent isn't non-toilet soap. Toilet soap can also be liquid soap. It took me all day to figure this out and understand what you were talking about.

Under toilet soap:

> In a domestic setting, "soap" usually refers to what is technically called a toilet soap, used for household and personal cleaning.

I'm not sure if that also includes detergent like dish detergent, but it's certainly not non-toilet soap.

Under non-toilet soap:

> Soaps are key components of most lubricating greases and thickeners. Greases are usually emulsions of calcium soap or lithium soap and mineral oil.[5] Many other metallic soaps are also useful, including those of aluminium, sodium, and mixtures thereof. Such soaps are also used as thickeners to increase the viscosity of oils. In ancient times, lubricating greases were made by the addition of lime to olive oil.[6]

> METALLIC SOAPS ARE COMPOUNDS OF ALKALINE metals or heavy metals and monobasic carboxylic acids containing from 7 to 22 carbon atoms. The water-insoluble metallic soaps are of particular interest to the coatings industry, although potassium and lithium soaps have limited water solubility.

They can also be lubricants for machines and you don't want to use any of this for cleaning anything at home.

Sorry, 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.

I don't see how his statement about antibacterial products is wrong. My grocery store, for example, sells hand soap in liquid pump dispensers. Some of these say antibacterial on the label and some of them don't. The antibacterial ones are very similar to the plain ones, except that they contain an ingredient which is of no use against viruses.

I think his point is that I have no reason to prefer the antibacterial one when my goal is to kill this virus. I'd say he's 100% right about that.

Reply on news.ycombinator.com