[HN Gopher] How many microbes does it take to make you sick?
___________________________________________________________________
How many microbes does it take to make you sick?
Author : meany
Score : 105 points
Date : 2023-10-01 16:03 UTC (6 hours ago)
(HTM) web link (www.quantamagazine.org)
(TXT) w3m dump (www.quantamagazine.org)
| curiousObject wrote:
| > _A tiny enough dose may even serve to remind our immune system
| of a pathogen's existence, boosting our antibody response to keep
| us protected against it._
|
| This article should be required reading, whatever your views on
| Covid and other conditions.
|
| Although the attack method of the infection is significant, and
| the potential victim's defenses are significant, the raw quantity
| of infectious agent and the exposure rate are also both important
|
| Nothing is certain. Everything is statistics.
| rand0mx1 wrote:
| It should be exposure time or do you mean something else with
| "exposure rate"
| wtallis wrote:
| "Exposure time" usually implies you're spending some period
| of time in proximity to an effectively unlimited reservoir of
| the pathogen (eg. an infected person coughing frequently) and
| your exposure is at some level of concentration that depends
| on the type/route of exposure, so that the total amount of
| pathogen that ends up in your body to challenge your immune
| system is proportional to the duration of time you spend
| being continually exposed.
|
| A phrase like "the raw quantity of infectious agent and the
| exposure rate" is calling attention to the fact that one
| brief intense exposure vs repeated small exposures over a
| long time span may have vastly different outcomes despite
| presenting your immune system with the same number of
| microbes to deal with.
| slim wrote:
| it could mean how many times you have been exposed to the
| virus in a month, for example
| Sakos wrote:
| This is one of the reasons why masks are so important and why
| they don't need to be 100% effective. Just reducing the amount
| of viral load could turn a serious infection into something you
| might barely notice.
|
| edit: Imagine this being controversial. I didn't realize there
| were Covid deniers and skeptics here, because what I've stated
| is completely within established science.
| explaininjs wrote:
| The simple fact of the matter is that having covid every now
| and then^ is far superior to wearing a mask always.
|
| ^ and the more you have it the less severe it is, until it
| asymptotically reaches a complete non-issue. As with the
| common cold.
| elsonrodriguez wrote:
| The exploration of truth is anathema to those who claim to
| already have the truth.
| meowkit wrote:
| Established science is an oxymoron.
|
| Science is an on going process, always open to being
| overturned.
|
| To the point of masks - I agree with your statement here, but
| a regular mask (filtered masks should help to some extent)
| will not protect you from an infected person. An infected
| person with a mask will reduce the chance of spreading their
| viral load.
|
| This detail is where I feel people are talking past
| eachother. Most of covid denial to me seems to be about a
| psychological reactance to being told to mask up when they
| are not sick.
|
| One might argue that the extra chance of reduced
| vectorization is worth mask mandates, but that simplistic
| purely "scientific" approach is its own problem. You have to
| argue people where they are at and convince them, not force
| the "right" view on them and then get upset they are "in
| denial" or skeptical.
|
| https://en.m.wikipedia.org/wiki/Reactance_(psychology)
| pton_xd wrote:
| > This is one of the reasons why masks are so important and
| why they don't need to be 100% effective. Just reducing the
| amount of viral load could turn a serious infection into
| something you might barely notice.
|
| It would be nice to have some numbers to back this up. Let's
| suppose the "viral load" to acquire a Covid infection is 18
| particles, the same as norovirus detailed in the article. And
| let's say you're exposed to hundreds of thousands of viral
| particles every minute you spend near a sick person [1]. If a
| mask reduces your viral load by 50%, is that a worthwhile
| method of avoiding infection?
|
| [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7598485/
| Jabbles wrote:
| From that link:
|
| _Our simulation also shows that wearing a mask can
| effectively reduce the spread of the viruses._
| pton_xd wrote:
| Sure, by some metric masks are very effective at stopping
| viral particles. After all, in my example the mask will
| stop tens of thousands of viral particles from reaching
| you every minute.
|
| Another metric is, will that stop you from getting sick?
| The threshhold is only 18 particles!
| sfblah wrote:
| There are good studies on viral load reduction from masking
| with flu viruses from before 2020. After 2020 the topic
| became politicized so the studies are probably unreliable.
| MrLeap wrote:
| The assertion is that if you dump a gooey grey gallon of
| pure covid on someone, their symptoms will be more severe
| than if they only get 18 virions. Do you suppose that
| wouldn't be the case?
| epivosism wrote:
| All the factors you mention are scalar. You can wear
| 0,1,2,3 masks. You can be 1,2,3,10,20 feet away from the
| person for 0,1,5,10 minutes. I can come up with any number
| of such factors involving wind, lifetime of virus, the
| person's shedding rate, etc.
|
| Given that, there will always be a border at which having
| an additional 50% coverage is useful. Where the actual line
| is, we don't know. But as long as protection is monotonic
| in the factors above, it's always valuable to have more
| protection, which implies even <100% effective masks are
| useful.
|
| Trivial proof: Imagine someone with literally 10k masks all
| around them. You have to admit this is more safe than 1
| mask. QED. You can call in meta factors like "in reality
| nothing matters" but you're arguing by consequences then,
| not actually disagreeing with the facts, just claiming they
| don't matter.
| sfblah wrote:
| What you said isn't controversial. It's definitely right.
|
| The issue with masks is one side started treating them like a
| talisman that makes infection impossible, which provoked the
| other side to say they do nothing.
|
| On a population level, masks are probably close to
| ineffective against a viral pathogen. You can read the
| relevant Cochrane review to see that.
|
| On an individual level they obviously do something, but you
| have to consider other factors as well, such as
| level/frequency of exposure and the like. Studies from prior
| to the pandemic suggested that a perfectly fitted N95 mask
| dramatically reduced flu virus penetration. For a more
| normally worn N95 the reduction was about 70%. For a surgical
| mask it was essentially nil. Importantly, a perfectly fitted
| mask required essentially gluing it to the face of a
| mannequin.
|
| Final point is, with an intervention whose impact is
| measurable but imperfect, you have to consider the side
| effects. I personally know several friends of my teenage kids
| who now have odd (to me at least) social phobias for which
| the only "cure" is to wear masks everywhere. Just last
| weekend I was talking to a friend of my daughter who wears
| masks everywhere except indoors.
| AnthonBerg wrote:
| The un-cited Cochrane review in question _does not_ say
| that.
|
| From Cochrane.org:
|
| _Statement on 'Physical interventions to interrupt or
| reduce ... - Cochrane_
|
| _Mar 10, 2023_
|
| _Many commentators have claimed that a recently-updated
| Cochrane Review shows that 'masks don't work', which is an
| inaccurate and misleading interpretation. It would be
| accurate to say that the review examined whether
| interventions to promote mask wearing help to slow the
| spread of respiratory viruses, and that the results were
| inconclusive._
|
| Repeating the important part:
|
| _the review examined whether interventions to promote mask
| wearing help to slow the spread of respiratory viruses_
|
| Conversely, here's a good study that shows that consistent
| use of FFP3 respirator masks _drastically_ reduced
| transmission among workers on a hospital ward:
| https://elifesciences.org/articles/71131
|
| Note that the study only had the workers wearing FFP3 masks
| on shifts, and community transmission was high at the time.
| Therefore the study "leaked" and good masks work better
| than the numbers in the study might seem to indicate. Face-
| fitting masks do work, and very well. Of course they do.
| It's all very clear if you dig into the aerosol physics.
| sokoloff wrote:
| It looks like FFP3 are analogous to N99 masks.
|
| A mask mandate that permits "wrap a piece of T-shirt over
| your mouth, some of the time, sometimes even covering
| your nose" (which is not far from what I saw for much of
| 2020) is, unsurprisingly, going to be more effective at
| ensuring grudging compliance with a mandate than it is to
| reduce the spread of an airborne virus.
| AnthonBerg wrote:
| Precisely.
| sfblah wrote:
| This is the problem with mask absolutists. They take data
| from masks that are super effective (hospital setting,
| correct usage, basically gluing the mask to your face)
| and extrapolate it to some guy on the subway with a cloth
| mask. It's a bad way to make public policy, and I don't
| really understand the motivation behind it.
| AnthonBerg wrote:
| I am not a mask absolutist.
|
| Close family is at risk of severe illness or death from
| COVID. We provide for a small child. We do not have much
| margin.
|
| I'd like to ask you to imagine the social repercussions
| of masking. It's _hard_. I do not want to be weird. I do
| not want to be an outcast, practically speaking. I don't
| want to wear a mask.
|
| I just don't have any margin in the other direction.
|
| Also:
|
| What is it about a hospital setting that makes a given
| type of mask more effective?
|
| Answer: Nothing.
|
| Hospitals are places where it's easier to run a trial,
| and where it's harder to avoid infection.
|
| Face-fitting masks do not require glue. Fitting a mask
| isn't that hard.
|
| Cloth masks don't work and never did.
|
| The objective is to not die or be maimed by a virulent
| pathogen, or rather: to have the option. Clarity on
| effective means for those who want it. I want effective
| means because I _need_ them. The objective is not social
| classification of mask wearers or categorization of
| discussion types or labeling people as cartoons.
|
| The objective is clear information as input into serious
| personal decision-making. The guy on the subway is not in
| scope.
| sokoloff wrote:
| I think hospital workers experience with wearing masks
| (and the resulting "they have chosen a mask size and from
| experience have adjusted the mask to make it comfortable
| and effective") and the ability for the hospital to
| prohibit facial hair in their workers that's incompatible
| with effective mask use are key differences between
| hospital staff and Joe/Jane Public on the streets.
|
| In terms of being weird: there are enough people wearing
| masks and most people literally care more about what
| they're going to have for dinner than whether or not
| you're wearing a mask. If a mask helps your family, don't
| worry about the epsilon weird aspect (as I'm sure you
| have already calculated).
| AnthonBerg wrote:
| Well said. Thank you.
|
| I think I can also pretty decisively say that hospital
| purchasing optimizations give face-fitting masks a bad
| rap. The FFP2 masks that hospital staff wear here are
| cheap and very uncomfortable. This bleeds into society as
| a negative view.
|
| There's also another aspect: The difference between a
| N95/FFP2/whatever mask as part of the industrial
| production of a verifiable sanitization chain in a
| hospital on one hand, and on the other as a piece of
| fabric that's ludicrously effective at stripping
| infectious particles from the air.
|
| There are many more edge cases in a hospital, and many
| more pathogens. In private life - mine at least - it's
| only really COVID that matters. In that case a mask can
| be reused again and again and it's OK to touch it,
| basically.
|
| --
|
| Re. being weird:
|
| I don't mind.
|
| The weirdness hurts the family. There's a big, big gap of
| dissonance between what we need to do and what public
| health authorities say. This includes flat out
| _demonstrably wrong_ statements about transmission where
| I live. This dissonance makes the family weird, and it
| has caused severe social isolation of a mother with a
| young child.
|
| I want to assure the reader that we don't ask for much.
| We are very, very polite. We don't demand anything, we
| are not difficult.
|
| It's purely the astounding dissonance. People don't know
| what to do and just fade away.
|
| It's a very painful way to be weird. You feel it in your
| bones and your soul how unnatural it is.
| sfblah wrote:
| Occam's razor here is that your interest in masks is a
| mental illness, and not because someone in your family is
| so immunocompromised or whatever that the mask is
| standing between that person and certain death. Is it
| possible that the latter is the case? Maybe. But in my
| view almost all cases of people stubbornly wearing masks
| are just psychiatric in nature.
|
| I know my comment will just make you angry, because
| "you're different". But, maybe someone else will see it
| and consider their psychological state on this topic.
| AnthonBerg wrote:
| I wish upon you severe illness and the humility to deal
| with the repercussions to your worldview, and happiness.
|
| I wish for your life to be long and healthy; and the
| lives of your loved ones too. And in that, let me give
| you advice to trade for your judgement of my place in
| life and my actions and sacrifices and loss. The advice
| is this:
|
| Read. The academic. Literature.
| sfblah wrote:
| I would encourage readers to read the "Main results"
| section of the review for themselves. It takes under 5
| minutes. Don't trust a commenter on any online forum on
| this topic (myself included), as it's completely
| politicized.
| AnthonBerg wrote:
| Also read the studies themselves.
|
| And the criticism of the Cochrane-method review.
|
| And the studies not cited.
|
| As well as the studies on the mechanics of transmission.
| sfblah wrote:
| I think people can rely on the authors to put the main
| results in the "Main results" section. What they can't
| rely on is potential nutters in Internet forums.
| rootusrootus wrote:
| > For a surgical mask it was essentially nil.
|
| Is the surgeon wearing a mask to protect himself from me,
| or to protect me from him?
| AnthonBerg wrote:
| The surgeon is wearing it because of an old, old
| misinterpretation of reality.
|
| This article is factually accurate:
| https://www.wired.com/story/the-teeny-tiny-scientific-
| screwu...
| stopping wrote:
| Your assessment is a non-sequitur to the article.
|
| Surgeons wear masks to protect the patient, because masks
| are very effective at trapping both droplets and aerosols
| that are emitted from the wearer. They are not designed
| to protect the user from lingering aerosols as masks are
| too loose to form a good seal, so most air breathed in
| simply enters from around the sides of the mask.
| AnthonBerg wrote:
| Surgical masks defined as the ones that gape at the sides
| are comparatively ineffective at stopping aerosolized
| particles.
|
| The idea that ballistic droplets are the primary means of
| infection is the old, old misunderstanding.
|
| If we compare the objective of preventing transmission of
| pathogens from surgeon to patient to the objective of
| covering nudity, surgical masks are as effective as
| shorts.
|
| Seeing as the objective is the objective, the ends should
| define the means. Therefore it is clear that any use of
| surgical masks is a fundamental and entrenched
| misunderstanding.
| stopping wrote:
| There are many studies which show that surgical masks are
| quite good at stopping a majority of expelled particles,
| even those well within the aerosolized size regime:
|
| Surgical masks reduce outward aerosol-sized particles by
| at least 74%:
| https://www.nature.com/articles/s41598-020-72798-7
|
| Surgical masks reduce outward COVID viral transmission by
| 73%, and viral RNA by 58%:
| https://journals.asm.org/doi/10.1128/msphere.00637-20
|
| Outward filtering efficiency above 50% is certainly worth
| it compared to the cost of a surgeon wearing a mask. It's
| arguably worth it even at much lower efficiencies.
|
| If you read my comment, you'll notice I'm not disagreeing
| on the aerosol/droplet size boundary. I'm arguing against
| the apparent subtext of your comment, which seems to
| indicate that surgical masks aren't effective at
| protecting patients.
| AnthonBerg wrote:
| Well said, thank you. Sincerely!
|
| I'd like to reiterate my analogy of the shorts :)
|
| Not least due to the subtle knock-on effects: surgical
| masks cast a fog on public awareness of face-fitting
| masks, which are superior in all respects (including
| comfort, which - case in point - came as a surprise when
| I tried one).
|
| --
|
| The effectiveness of face-fitting masks is so much
| greater that I honestly regard the use of surgical masks
| as morally indefensible.
| maxerickson wrote:
| _which provoked the other side to say they do nothing._
|
| This somewhat excuses their reactionary stupidity. Like
| they weren't "provoked", the use of masks wasn't directed
| at them.
| sfblah wrote:
| Where I live, in Alameda County, California, masks were
| required outdoors if you were within 30 feet of another
| person. This ridiculous policy lasted about a year and
| provoked all kinds of altercations. It also made
| exercise, a key way to say fit, much more difficult. So,
| in this case I would argue mask use was in fact "directed
| at" people.
| maxerickson wrote:
| When you say that, you are saying that the policy was put
| in place in bad faith in order to inconvenience the
| people that didn't like it. The argument is more
| ridiculous than the policy.
|
| Here there was never an outdoor mask policy, so I didn't
| ever have a chance to evaluate my reaction to such a
| thing. There was apparently a policy banning stores like
| Walmart from selling seeds (which I interpreted as
| bureaucratic friction rather than intention, something
| that was born out relatively quickly in practice, and
| never in the minds of the reactionaries).
| sfblah wrote:
| There's a fine line between a policy being intended to
| harm and just being stupid. Regardless of the rationale,
| I was just trying to demonstrate how such policies were
| in fact weaponized.
|
| You can do some reading about the Bay Area and debates
| over whether government policies are in bad faith. I
| think it's at least arguable that some are in fact in bad
| faith (meaning, no one really thinks they'll serve any
| public purpose other than punishing groups of people).
| jeffbee wrote:
| Nothing was "weaponized" by this order, which 100% of
| people ignored.
| sfblah wrote:
| I wish what you were saying were true, but it just isn't.
| I'm a fairly serious runner -- 40-60 miles per week
| typically. The amount of nonsense I experienced during
| that year might surprise you. Dozens of different times I
| was yelled at on trails, in the street, etc. because I
| was "too close". I was threatened with violence multiple
| times. This was all in the context of trying as hard as I
| could in all cases to stay as far from people as possible
| -- 10 feet minimum -- and to pass them as expeditiously
| as I could. I avoided narrow trails in parks completely,
| etc. People went insane, and it was absolutely due to
| this policy.
| AnthonBerg wrote:
| That's bad policy, and obviously harmful.
|
| There we are in perfect agreement.
|
| That policy is also obviously at odds with scientific
| knowledge.
|
| Policies like that harm high-risks groups immensely too.
|
| Over here, the bad policies were strict social
| restrictions. Baseless and arbitrary restrictions of the
| number of people allowed to be at funerals and strict and
| severe limits to hospital visits. None of these were
| necessary from the perspective of the reality of
| aerosolized transmission and how easy it is to strip the
| pathogen out of the air we breathe.
|
| It's so absurd that it took a long time to find an
| analogy. It's like repairing the flat tire on your bike
| with a patch of sod. It doesn't really work, it's messy,
| and people will think you're crazy.
| msie wrote:
| That Cochrane review is faulty and one of the co-authors
| (Tom Jefferson) "works for the Brownstone Institute, a
| Covid-19 misinformation group that is powered by dark
| money."
|
| https://www.theguardian.com/commentisfree/2023/feb/27/dont-
| b...
| jimwhite42 wrote:
| As far as I can tell, the issue is people misrepresenting
| what the review says, not that the review is faulty.
|
| The review concludes that we have evidence that masks are
| effective, but the set of papers reviewed cannot be used
| to conclude we know the level of effectiveness enough to
| make accurate judgements on tradeoffs in many of the
| kinds of situations where people were asked to wear masks
| in the pandemic. So we don't know enough yet.
|
| I read a bunch of the criticisms of this paper and
| criticism of the anti-maskers misrepresentation of what
| it said, and none of the ones I found suggested that
| there were missed papers which provide the precision the
| review didn't find.
|
| The Guardian article is a mixed bag in my opinion. It
| tries to get around the idea that we really need more
| research, it confuses a lot of things.
|
| (BTW, I am not an anti masker, I wore a mask, I find
| people who whine about wearing them to be a bit pathetic
| most of the time.)
| [deleted]
| User23 wrote:
| RCTs show surgical and cloth masks to be ineffective or
| nearly so for reducing the spread of respiratory viruses.
| Obviously the kinds of masks used in BSL labs do work to
| prevent spread.
|
| However there are statistics that areas with more masking had
| less severe illness. However that's uncontrolled and some
| other factors or factors might account for both increased
| masking and reduced spread. That's probably the case
| otherwise the RCTs would show efficacy.
|
| All of the subsequent work is just computer models and
| doesn't actually tell us anything empirical. Obviously it's
| easier to create a model that produces the desired result
| than it is an RCT.
| mozman wrote:
| There shouldn't be any requirements for masks. Want to wear
| one? Great. Should I have to? No.
| amanaplanacanal wrote:
| Is fairly common that, if you as an individual are doing
| something that poses a risk to other people, society will
| step in to attempt to change your behavior. You can argue
| that it is "wrong" for society to do that, of course.
| maxerickson wrote:
| So people shouldn't have freedom of association or control
| over their own property?
|
| Or do you just mean universal requirements imposed by
| society at large when you say 'any'?
| dorfsmay wrote:
| > boosting ourantibody response
|
| What I wonder is if we can develop immunity (not boosting,
| assuming never been infected before) from being exposed to
| small doses, or do we need at least one full blown infection.
| jameshart wrote:
| Not sure why you are suggesting the basic mechanism of
| inoculation, which has been known for centuries and is the
| fundamental mechanism behind vaccination, as if it's a novel
| hypothesis. Have I misunderstood what you're getting at?
| beebeepka wrote:
| I think your understanding is fine. A friend of my wife
| once came up with the novel idea of renting books out of
| big buildins that are loaded with books. Brain farts happen
| to all of us
| dorfsmay wrote:
| Dosage. Vaccines use deactivated viruses, but I don't think
| they use "tiny amount".
| kbutler wrote:
| https://www.cdc.gov/smallpox/history/history.html
|
| To test his theory, Dr. Jenner took material from a
| cowpox sore on milkmaid Sarah Nelmes' hand and inoculated
| it into the arm of James Phipps, the 9-year-old son of
| Jenner's gardener. Months later, Jenner exposed Phipps
| several times to variola virus, but Phipps never
| developed smallpox. More experiments followed, and, in
| 1801, Jenner published his treatise "On the Origin of the
| Vaccine Inoculation." ... Vaccination became widely
| accepted and gradually replaced the practice of
| variolation. At some point in the 1800s, the virus used
| to make the smallpox vaccine changed from cowpox to
| vaccinia virus.
| vikramkr wrote:
| Yep that's called vaccination! No need to get a full blown
| infection it's how we eradicated smallpox
| dilyevsky wrote:
| That's not vaccination that's inoculation which is how they
| originally prevented smallpox before they developed an
| actual vaccine
| vikramkr wrote:
| Its responsive to the parent question in that yes, we can
| have symptomless exposure to the infectious agent (or
| some part of it) and develop immunity. Maybe the
| distinction between using unweakened live pathogens and
| weakened or fragmented pathogens should have been
| emphasized but that didn't seem to the important part of
| the question
| dorfsmay wrote:
| Thanks, that was indeed my question.
|
| It'd be interesting to understand if that's true for all
| viruses and in what quantities.
|
| For example, in the early days of COVID, we were told
| that being close to infected people outdoor did not
| expose us to enough viruses to get infected. Could such
| exposure have provided immunity?
| dorfsmay wrote:
| Vaccination is using deactivated viruses. My question is
| can we get the same effect from exposure to small doses of
| live viruses.
|
| The articles says exposure to tiny amount can "boost"
| immunity, which I assume means an immunity acquired earlier
| from a full blown infection (or vaccination).
| maxerickson wrote:
| Vaccines are rooted in a history of doing exactly what
| you are talking about. Smallpox variolation was done for
| hundreds of years before the development of the first
| vaccine.
|
| https://www.cdc.gov/smallpox/history/history.html
| southernplaces7 wrote:
| As with many things in medicine, it depends on specifics
| and context. With some viruses, this might work, and with
| others it could kill you. Vaccination itself is tricky
| partly for this very reason as far as I know (not a
| doctor or epidemiologist).
|
| Variolation for example, the predecessor to the world's
| first practice of vaccination (against smallpox) involved
| taking tiny amounts of live smallpox from scabs or
| pustules and giving them to people intentionally for a
| much lighter infection course that made them immune
| without the usually killing or horrifically disfiguring
| blow of a full smallpox infection. (look up photos of
| smallpox scars in survivors, warning, it gets graphic.
| Even many famous figures like Stalin were completely
| pockmarked by the scars of the virus for the rest of
| their lives, as you can see in unedited photos of the
| dictator)
|
| It usually worked, but sometimes the patients got really
| sick anyhow and died. By the standards of the time, when
| fully a third of the population could expect to die from
| some epidemic disease or another, this was considered
| wonderful. Today it wouldn't be and thus the complexities
| of carefully calibrating vaccines.
| ABCLAW wrote:
| Vaccination generally uses an adjuvant to increase immune
| response to the target antigen in order to provoke a
| response strong enough to produce lasting immunogenic
| memory. Antigens alone in small numbers aren't enough.
|
| Taking random adjuvants consistently after minimal
| exposure to environmental antigens is more likely to give
| you deleterious allergies or issues associated with
| chronic inflammation.
| malfist wrote:
| Vaccination can use deactivated viruses, but not always.
| yieldcrv wrote:
| I've gotten lots of anti vaxxers to be into vaccines by
| saying what the parent said, most of them are just allergic
| to the word vaccine and don't know what it means,
| (specifically I'm referring to using dead pathogens not
| just a low dosage of live ones)
|
| so just describe the procedure, and call it a secret that
| big pharma doesnt want them to know, and theyre into it. be
| anybody but a doctor lol
|
| slam dunk
| dorfsmay wrote:
| I'm not anti vaccine, no need to out words in my mouth.
|
| My understanding of vaccine is that they use deactivated
| viruses but not small doses.
|
| My question is about live viruses, and if we can get
| exposed to small doses enough that will trigger a
| immunization mechanism without triggering a full blown
| infection? Or does it work to boost an existing immunity
| only.
| api wrote:
| There are many different kinds of vaccines that work in
| slightly different ways. "Vaccine" is a class of
| treatments akin to "anesthetic" or "antibiotic."
|
| Some are weakened live agent. Some are killed or
| neutralized agent. Some are just a protein or other piece
| of the pathogen. Some like mRNA vaccines are code from
| the pathogen that causes your body to generate and then
| sensitize against something. There are probably other
| types.
|
| I do find the oversimplification in the debate
| frustrating. Either all vaccines are bad or all vaccines
| are great when in reality each one is a different thing.
| As with other drugs some work better than others and some
| have side effects while others mostly do not.
|
| As near as I can tell the mRNA COVID vaccine is fairly
| effective at reducing severity and duration of infection
| but not nearly so at completely preventing infection.
| There is a small risk of side effects but the danger from
| a more severe COVID infection is statistically much
| greater.
|
| Creating a vaccine in a year is nuts. What we came up
| with is not half bad given that time frame. We will
| probably have much better COVID vaccines in a few years.
| XorNot wrote:
| It's quite possible the biggest issue with the COVID
| vaccines we have is that intramuscular injection produces
| a blood-borne immune response but the method of infection
| is through the lungs, and you get much less response
| there.
|
| It's why there's been a lot of interest in inhalable
| vaccines[1] although getting them to market has had a lot
| of delays.
|
| [1] https://www.nbcnews.com/health/health-news/nasal-
| covid-vacci...
| [deleted]
| uuuuuuuiiiiii wrote:
| [dead]
| uuuuuuuiiiiii wrote:
| [dead]
| zby wrote:
| If 400 microbes that contact your body makes you sick - then what
| if one virus gets into a cell and produces 400 copies? It is
| certainly possible: "For example, SIV, a cousin and model for the
| HIV virus, is released from infected T cells with a burst size of
| [?]50,000 (BNID 102377) whereas cyanobacterial viruses have
| characteristic burst sizes of [?]40-80"
| http://book.bionumbers.org/how-many-virions-result-from-a-si...
| So if not just one - then a few initial virions should be able to
| produce the infectious dose.
|
| I guess time is important here - the organism detects the initial
| virions and prepares defences - so if the infectious dose amount
| of virions comes after the organism is warned they fail to grow
| into an infection. But my intuition is that the complexity of
| that process and path dependence makes that infectious dose so
| variable - that it does not seem to be any useful.
| XorNot wrote:
| No this is all statistics again: probability that a viral
| particles survives in the body, probability that it
| successfully enters the cell (this is all chemical kinetics so
| it's not 100%), probability the cell survives long enough to
| replicate the virus, probability of an immune response picking
| up the lyzed cell immediately and then repeat for the daughter
| copies.
|
| An analogous process would be human fertilization: it
| technically only takes 1 sperm to fertilize an egg, but it's
| millions in order to make the probability of it happening
| meaningfully high enough.
|
| Of course some viruses are stupidly good at this: it's
| estimated 5 norovirus particles will trigger a full blown
| infection.
| [deleted]
| gregwebs wrote:
| Great to see statistical thinking. There have been a lot of Covid
| shouting matches because people are trying to reduce things to
| binary. Masks don't work! Actually, they work as advertised- only
| 95% effective at best (and a cloth mask may be 30%), not a binary
| protected or not. That's effective at blocking particles. You are
| still guaranteed to get some virus particles. They are going to
| be in your respiratory tract trying to replicate, and maybe some
| are replicating-does that mean you are infected in a clinically
| meaningful way? Depends.
|
| Researchers will try to measure if some intervention like that
| works reporting binary PCR positive or negative- but we should
| want to know what was the severity of the illness. PCR positive
| with minor illness can be a good outcome indicating that the
| intervention helped lower the innoculum.
| macawfish wrote:
| I don't know if I'd call this "statistical thinking", at least
| not in the conventional sense of linear statistics with simple
| parametric models. If anything I'd call this "systems
| thinking", which unfortunately is not the kind of thinking I
| typically associate with "statistical thinking".
| PaulKeeble wrote:
| Actually N95 is AT LEAST 95% effective. 95% is its worst case
| performance on a PM2.5 sized particle, at all other particle
| sizes it is better than 95% usually considerably. We also have
| N99 masks and even P100 respirators which do an even better
| job. We just need to start using them. We also need to educate
| ourselves how to fit and fit test a mask because if its leaking
| its not giving you that level of protection.
| weaksauce wrote:
| you're absolutely correct and furthermore smaller particles
| and larger particles are easier for the masks to catch to
| state it differently if it wasn't clear.
| hamburglar wrote:
| Well, the actual mask's performance is 95% effective, but you
| can't really make a guarantee about the overall worst case
| effectiveness when deployed by humans. N95 masks are not 95%
| effective on someone who has a big fluffy beard preventing a
| proper seal, for example. Or with people who use their gut
| feeling to decide where and when to put them on (like
| deciding if there's nobody in the elevator, you don't need
| it, ignoring the fact that someone may have gotten out of the
| elevator 20 seconds ago and left particulates in the air).
| avereveard wrote:
| I think that's about the material itself, then at the mask
| face interface you get all kinds of sealing issues
| swayvil wrote:
| There is also bodily vigor to consider.
|
| When you are strong you are resistant. When you are weak you are
| susceptible. The difference can be huge.
|
| It's a good argument for clean living, regular exercise etc.
| angst_ridden wrote:
| Being in excellent health can increase the required pathogen
| dose, and help resist illness. It can also, paradoxically,
| cause worse results. See, for example, "cytokine storm."
| roywashere wrote:
| When I was sixteen I sailed a lot on the lakes in my
| neighborhood. I was strong and healthy and thought: what could
| microbes do against 1 meter 90 of me? So I drank the water from
| the lake to see what would happen. I became rather sick to my
| stomach :-) and I considered defeat
| yjftsjthsd-h wrote:
| The claim was _increased_ resilience, not perfect immunity.
| smegsicle wrote:
| about how much lakewater are we talking
| brewdad wrote:
| For Covid, yes. If we look at the 1918 flu pandemic, the worst
| affected populations were those young adults with strong immune
| systems. They basically went into overdrive and the bodies
| attempts to fight the infection caused irreparable damage to
| the host.
| user_7832 wrote:
| Why is this downvoted? Hygiene and exercise is sound advice
| that any doctor'd agree with.
| extrememacaroni wrote:
| Probably because the poor guy's theory isn't true for all
| possible cases ever, isn't peer reviewed etc.
| dbsights wrote:
| I think the portraits of the downvoters would fully explain
| this phenomenon
| sulam wrote:
| Just keep in mind, dose-dependence is variable. It's not a virus,
| but even one cryptosporidium oocyst is enough to get you sick.
| thenerdhead wrote:
| > Exposure is a function of pathogen concentration and contact
| time, so if you can reduce either of those, you can better avoid
| infectious diseases.
|
| What these articles don't talk about are the real-life challenges
| of concentration and contact time. For example, being a parent
| with a kid in school they might randomly sneeze or cough in my
| face while being completely asymptomatic. Then of course we all
| come down with covid later on.
|
| Secondly, the claims about viral load and shedding have
| conflicting science on new variants too:
|
| > https://www.nature.com/articles/s41591-022-01816-0#Sec7
|
| i.e
|
| > Nevertheless, in our study, correlation between RNA and
| infectious VL was equally low between fully vaccinated and
| unvaccinated Delta-infected patients, indicating that factors
| other than mucosal neutralizing antibodies may be important for
| the reduction in infectious VL
|
| > Within 5 DPOS, we found higher RNA VLs but lower infectious VLs
| in swabs of unvaccinated patients with pre-VOC infections
| compared to Delta. These results disagree with other studies that
| analyzed only nucleic acid detection and found 3-10-fold-higher
| RNA copy number in Delta-infected patients compared to pre-VOC-
| infected patients
|
| > Although VL is a key element of transmission, the process of
| human-to-human transmission is complex, and other factors, such
| as varying recommended protection measures, overall incidence,
| perceived risks and the context of contacts (household versus
| community transmission), can influence outcomes in the studies
| reported.
|
| The best point from this article is the following:
|
| > Transmission dynamics are complex, but the interventions we can
| take to protect ourselves are comparatively simple.
| PaulKeeble wrote:
| Last paragraphs are really important recommendations for how to
| end the pandemic.
|
| "Masking, increased ventilation and distancing reduces the number
| of microbes you're exposed to. Vaccination increases the
| infectious dose. "
|
| We really need to move beyond vaccine only, its not working Covid
| is just too transmissible.
| amanaplanacanal wrote:
| Ventilation changes seem like a big deal. Unfortunately that
| requires businesses and government to spend money, instead of
| putting the burden on individuals. This would require
| regulatory action, and at least in the US we have important
| culture wars to fight instead.
| HocusLocus wrote:
| Just one if it's a big one
___________________________________________________________________
(page generated 2023-10-01 23:01 UTC)