11 ms·

Imperfect Vaccination Can Enhance the Transmission of Highly Virulent Pathogens (2015)

90 points by jules-jules 5y ago

mdeck_ 5y ago
Needs a (2015) in the title.
rgbbtc4life 5y ago
This is the point in the story where all the vax naxis eat crow. Better luck next time, enjoy your ade.
JohnJamesRambo 5y ago
>Our data show that anti-disease vaccines that do not prevent transmission can create conditions that promote the emergence of pathogen strains… This isn’t remotely what we are dealing with with regard to Covid vaccination. In fact the opposite. That’s my understanding of it.
- a41cf 5y ago
  > this isn't remotely what we're dealing with Citation needed. More and more evidence is emerging that the vaccinated that get infected can spread it. Worse yet a so-called "breakthrough" can be asymptomatic [0]. There's still research to be done but this is the actual current up-to-the-minute consensus. If this is true then, not having a biology degree, I would assume that because these do not prevent spreading but rather mitigate severe illness those people who are infected and vaccinated are more likely to be responsible for transmitting it as there won't be many, or any, symptoms to signal you to quarantine/get tested. Moreover, historically there have been several leaky vaccines that have contributed to far more fit viruses. We could possibly be staring at the biggest health science flub in history. [0] https://www.jhsph.edu/covid-19/articles/new-data-on-covid-19-transmission-by-vaccinated-individuals.html https://www.jhsph.edu/covid-19/articles/new-data-on-covid-19...
- slumpt_ 5y ago
  Yep. Spoke with someone who worked on the Moderna vaccine about this. The short of it is, the window in which the virus can / has an opportunity to mutate is shortened by the vaccine. Thus, vaccinated individuals may be host to mutations if they catch COVID but given fewer “dice rolls” - if you want to call it that - would be similarly less likely to create an especially worse mutation. Couple that with the reduction of spread given by vaccines, and the difference is staggering. This paper is being wildly misinterpreted and cherry-picked by people who aren’t involved in the science, or qualified to consume it.
  - f6v 5y ago
    > This paper is being wildly misinterpreted and cherry-picked by people who aren’t involved in the science, or qualified to consume it. These days everyone is a vaccine expert and climate change scholar.
    - ryanobjc 5y ago
      I’m a bit concerned as to what it really says that this is front over material on hn. The short of it, is suspect a substantial sub population here are holding a variety of opinions that ultimately result in vaccine reluctantance. While the numbers aren’t so fast as to be significant to public health, I do think it forms a sort of idea laundering or affirmation by social proof. In other words people are using the reputation of hacker news for having smart people to launder and promote anti vax.
      - haswell 5y ago
        And yet, the problematic aspects of the paper are being highlighted by the readers here. Many things make it to the front page of HN because they’re interesting. That doesn’t mean that the readership is endorsing problematic viewpoints.
      - __blockcipher__ 5y ago
        Interesting you're so focused on the "vaccine hesistancy" side of the fence. Do you have any concerns about people using their prestigious degrees and credentials to frighten the population completely out of proportion with their actual risk from a pathogen, in order to persuade them to comply with top-down public health measures? It sounds a lot like you just don't like the conclusion that this classic paper leads to: that the "societal benefit" of mass vaccination with an imperfect vaccine is not nearly as clear-cut as many have been led to believe. My advice to people is to treat the vaccines as a personal risk reduction tool and little else. The only way to actually guarantee you won't infect someone you interact with, is to have acquired (and recovered from) the natural SARS-2 virus, which will build robust immunity. As far as immunity to reinfection, looking at antibodies alone, IgG levels stay seropositive for ~3.5 years: https://www.medrxiv.org/content/10.1101/2020.07.18.20156810v1.full.pdf https://www.medrxiv.org/content/10.1101/2020.07.18.20156810v... > Based on these half-life data, we estimate that the median times for IgM, IgA and IgG to become seronegative are 4.59 (IQR 4.12-5.03), 7.78 (IQR 6.71-9.16) and 42.72 (IQR 33.75-47.96) months post disease onset. > This study suggests that SARS-CoV-2 infection induces robust neutralizing and binding antibody responses in patients and that humoral immunity against SARS-CoV-2 acquired by infection may persist for a relatively long time. and furthermore once those IgG levels fade you will still have immunological memory, which lasts basically forever and allows your system to much more rapidly and effectively respond to future infection, leading you to have a much lower peak viral load, lessened symptoms (usually fully asymptomatic) and therefore a near inability to transmit the virus. For example for the 1918 flu, immunological memory has been shown to persist 60+ years later: https://www.cidrap.umn.edu/news-perspective/2008/08/researchers-find-long-lived-immunity-1918-pandemic-virus https://www.cidrap.umn.edu/news-perspective/2008/08/research...
- perihelions 5y ago
  Your understanding is 100% correct. Moreover, last I read about it, covid's peak viral shedding was in the pre-symptomatic or early symptomatic stage -- it's most infectious in walking, healthy-ish people. https://www.cidrap.umn.edu/news-perspective/2020/11/covid-19-most-contagious-first-5-days-illness-study-finds https://www.cidrap.umn.edu/news-perspective/2020/11/covid-19... (The submitted paper is about "highly lethal pathogens" where "host death greatly reduces transmission". That's the opening line of the abstract, and I'm baffled how anyone would link this to covid). (edit: first version had a horrific typo, /s/incorrect/correct/)
  - JohnJamesRambo 5y ago
    I don't see anything in that about vaccinated people. https://www.osfhealthcare.org/blog/fully-vaccinated-less-likely-to-pass-covid-19-to-others/ https://www.osfhealthcare.org/blog/fully-vaccinated-less-lik... >“We do not have conclusive proof. But more and more studies and real-world evidence points to fully vaccinated people, who are not immunocompromised, are less likely to transmit the virus if they become infected,”
    - perihelions 5y ago
      I've edited my comment (there was a horrific typo) -- I 100% agree with you. Covid is *not* disease like Ebola, whose transmission is self-limiting by its lethality -- it's the opposite.
      - __blockcipher__ 5y ago
        It's not as simple as lethality. Generally a pathogen needs to cause some sort of symptom in the host to spread well, but the more severe the symptoms the more aggressively the person would isolate. Insofar as the vaccines mostly worked upon their initial release, you can imagine a new strain that is much more virulent (replicates significantly faster, etc); such a strain could cause a vaccinated individual who would normally be completely asymptomatic and therefore not infectious [hopefully we all accept by now that there is pre-symptomatic spread but not asymptomatic spread, if not you're behind a year on the research], to become symptomatic and therefore capable of transmitting. If that same strain were to infected an unvaccinated individual who had never been exposed to the real virus, it might cause much more severe symptoms in them. --- There's also the separate phenomenom of immune escape. The current major vaccines (mRNA and adenovirus-vector) all just make the body's own cells express (generate) the spike protein (S2 subunit), and nothing else. So specifically point mutations in the S2 subunit could allow some degree of artificial immunity evasion (it wouldn't work against those naturally infected because they were infected with whole, live-replicating virus and thus have much more diverse epitopes for their immune system to "learn" and possibly a stronger immune stimulus in the first place)
deleted 5y ago
[deleted]
dasudasu 5y ago
>Vaccines that let the hosts survive but do not prevent the spread of the pathogen relax this selection, allowing the evolution of hotter pathogens to occur. This type of vaccine is often called a leaky vaccine. When vaccines prevent transmission, as is the case for nearly all vaccines used in humans, this type of evolution towards increased virulence is blocked. But when vaccines leak, allowing at least some pathogen transmission, they could create the ecological conditions that would allow hot strains to emerge and persist. Very relevant when coupled with the Massachusetts study that showed that the vaccinated can still spread Delta with apparently very little problem. https://www.cdc.gov/mmwr/volumes/70/wr/mm7031e2.htm?s_cid=mm7031e2_w https://www.cdc.gov/mmwr/volumes/70/wr/mm7031e2.htm?s_cid=mm...
- 0x_rs 5y ago
  I certainly hope the similarities with Marek's disease reaching 100% mortality begin and end there. What I can personally extrapolate is that allowing or even advising vaccinated people not to wear masks and distancing is rather dangerous. https://en.wikipedia.org/wiki/Marek%27s_disease#Diagnosis https://en.wikipedia.org/wiki/Marek%27s_disease#Diagnosis
  - __blockcipher__ 5y ago
    Masking has never been sufficiently proven to be effective against the spread of respiratory viruses. For SARS-2 specifically we have one randomized controlled trial, DANMASK, which showed no effect of masking (note the primary endpoint was self-infection not community transmission, but self-infection is a decent proxy, and furthermore community transmission is incredibly difficult to study, which is why it is so evil to me that the public health establishment convinced people that "my mask protects you, but not me" when there's actually never been evidence that it protects others as evidenced by the utter lack of studies on that part specifically) For the pre-2020 studies, they were more or less in agreement that masks didn't help, even in healthcare workers, who tend to be better trained and more compliant with masking protocols. Indeed Macintyre et al provides strong evidence of the risks of cloth mask wearing; while this study compared cloth masking to standard practice, not no-masking, it at a minimum establishes the very real risks of cloth mask wearing: https://pubmed.ncbi.nlm.nih.gov/25903751/ https://pubmed.ncbi.nlm.nih.gov/25903751/
buu700 5y ago
Sounds similar in principle to the consequences of failing to complete a course of antibiotics.
- prox 5y ago
  Nope. Please read the top 2 answers in today’s askscience : https://www.reddit.com/r/askscience/comments/ozh9mi/is_the_delta_variant_a_result_of_covid_evolving/ https://www.reddit.com/r/askscience/comments/ozh9mi/is_the_d...
  - xdennis 5y ago
    A subreddit that's full of [deleted] isn't trustworthy. Unlike HN, non-admins can downvote posts they don't agree with on Reddit. A subreddit full of [deleted] indicates it's one sided.
    - prox 5y ago
      Normally perhaps. But this is askscience, which just has a high standards when it comes to answers.
      - smaryjerry 5y ago
        I’m not sure about askscience but the “science” Subreddit is completely partisan and non ruled. And the science is still changing, delta is brand new. These vaccines weren’t made for Delta at all and aren’t stopping transmission, however they do offer protection from symptomatic disease, per the CDCs own documents and new recommendation that vaccinated wear masks indoors. Per this Washington post aritcle 75 percent of new cases in highly vaccinated Singapore are in already vaccinated people, similar to the unpublished CdC internal data which made the CDC revise their mask recommendation. https://www.washingtonpost.com/health/2021/07/29/cdc-mask-guidance/ https://www.washingtonpost.com/health/2021/07/29/cdc-mask-gu...
    - jdavis703 5y ago
      Users with enough Karma are allowed to downvote on HN. That’s what the gray replies are.
thedream 5y ago
Another thing that Can Enhance the Transmission of Highly Virulent Pathogens: letting 399 unwitting human beings carry Syphilis for years while you treat them like lab rats[1]. [1] https://www.cdc.gov/tuskegee/timeline.htm https://www.cdc.gov/tuskegee/timeline.htm
nathanfig 5y ago
> Conventional wisdom is that natural selection will remove highly lethal pathogens if host death greatly reduces transmission. Vaccines that keep hosts alive but still allow transmission could thus allow very virulent strains to circulate in a population. Host death does not stop transmission of Covid-19 so I do not think this study is particularly relevant, if we’re reading it in that context.
- jhgb 5y ago
  But perhaps partial vaccination has a similar effect if you make transmission less likely and now only more transmissible mutations make the cut.
  - noduerme 5y ago
    This is true, and I wonder whether partial vaccination didn't play a role in the rise of Delta. But more transmissible != more lethal.
    - jhgb 5y ago
      In the case of Delta it almost certainly didn't. But the fact that something happened through one mechanism doesn't mean that it can't happen through another mechanism.
  - sweetdreamerit 5y ago
    Am I wrong if I think that the most transmissible mutations tend to win the competition towards the less contagious ones in any case?
- __blockcipher__ 5y ago
  > Host death does not stop transmission of Covid-19 Huh? It does for that host. Yeah their corpse can still spread it for awhile or whatever but they're no longer engaging in society.
  - jdavis703 5y ago
purple_ferret 5y ago
I know this is making the rounds of the 'covid vaccine bad'[0] crowd, but isn't it the case that the yearly flu vaccine doesn't guarantee immunity? How has such a vaccine been flying by with such a potential danger present? [0]https://youtu.be/tiwsv51Il4k?t=98 https://youtu.be/tiwsv51Il4k?t=98
- thisiscorrect 5y ago
  What fraction of people take the annual flu vaccine?
  - djrogers 5y ago
    That’s a pretty straightforward question to find the answer to - it’s just a bit under half, whith kids and seniors being more likely to get it. [1] https://usafacts.org/articles/how-many-americans-get-flu-shots-vaccine-cdc/ https://usafacts.org/articles/how-many-americans-get-flu-sho...
- curmudgeon22 5y ago
  I don't believe it's a matter of 100% guarantee of immunity. The current covid vaccines are designed to prevent severe infection, NOT prevent infection. My understanding is that the current vaccines ~95% efficacy is against severe infection, but we don't actually know what the efficacy against infection is. If you compare this to say smallpox vaccine, it is 95% effective at preventing infections. https://www.health.ny.gov/publications/7022/ https://www.health.ny.gov/publications/7022/
  - krona 5y ago
    The 95% efficacy statistic was ultimately a positive PCR test, i.e. infection or a 'case' of the disease.
    - curmudgeon22 5y ago
      Yes, but only symptomatic folks were tested.
Rd6n6 5y ago
I have been assuming the idea of these vaccines was to buy time until a new one gets developed that also stops transmission. Ie, I assume we will all get a second vaccine one day that’s better that can have a shot at wiping Covid out, if we get really lucky and everyone takes it
- thisiscorrect 5y ago
  The likelihood of wiping out (as in, totally eradicating) a respiratory infection seems really low. Are there any examples of that happening in the past?
  - jdavis703 5y ago
    The original SARS virus was eradicated.
    - ekianjo 5y ago
      nope it died out.
xdennis 5y ago
Why do these things keep coming out AFTER I've already taken a dose?
kleene_op 5y ago
It is not very difficult to imagine that antivaxxers would use this article as proof that vaccination was a mistake and that we should not go further. However, this bit: > Our data show that anti-disease vaccines that do not prevent transmission can create conditions that promote the emergence of pathogen strains that cause more severe disease in unvaccinated hosts. Actually makes a convincing case for anyone who did not get the vaccine to get it. Anyway, that won't convince hardcore antivaxxers, so we shall see in the upcoming months/years whether this article actually transposes to our situation. Just a shame this may be happening at the expense of gullible yet still good at heart people.
- thisiscorrect 5y ago
  The rub is that there are a lot of people on Earth. And, early evidence _might_ suggest that the vaccines that are available lose effectiveness sooner than originally thought. For example, [1] shows evidence of diminished effectiveness after 146 days. Back to "Our data show that anti-disease vaccines that do not prevent transmission can create conditions that promote the emergence of pathogen strains that cause more severe disease in unvaccinated hosts." and whether that implies that "for anyone who did not get the vaccine to get it." This sounds like a strategy that hinges on everyone on Earth getting vaccines and frequent-enough booster shots. What if that's unachievable though? The logistics for that would be unprecedented. What are the consequences of trying but failing to do it? [1] https://www.medrxiv.org/content/10.1101/2021.08.03.21261496v1 https://www.medrxiv.org/content/10.1101/2021.08.03.21261496v...
  - jacobolus 5y ago
    > lose effectiveness sooner than originally thought To be precise, have partially reduced effectiveness against transmission of a variant of the virus evolved after the creation of the vaccine, while still preventing almost all severe illness/death. Possible ways forward: (1) give people additional booster shots of the existing vaccine; (2) develop a modified vaccine booster targeted more precisely to the variant virus; (3) keep public health measures in place (e.g. requiring everyone to wear face masks indoors) so long as Re > 1. > What if that's unachievable though? It has been more or less achievable for past vaccinations. It is a logistical challenge to be sure, but modern society is certainly capable of it if it is prioritized.
mrosett 5y ago
I love this kind of stuff intellectually -- deep dives on how edge cases can produce counterintuitive results. But I'm surprised to see HN uncritically assume this is relevant to Covid [1]. This article deals with viruses that have trouble spreading because they kill the victim too quickly. That's manifestly not the case with Covid, which (when compared to really nasty things like ebola or apparently Marek's) kills a relatively low share of its victims and isn't particularly quick about it. [1] Or at least the top two top-level comments do as I'm writing this.
__blockcipher__ 5y ago
For those decrying the fact that this study is about a highly deadly virus, note that mathematically speaking, the same effect would be expected to be observed for a much less obviously lethal virus, if the effect were occurring across billions of hosts, such as what we're currently pushing for globally with the mass COVID vaccination campaign
lmilcin 5y ago
It is all very simple really. Whatever we do, if we do not do it decisively, we just give the virus occasion to adapt. population of hosts * selection pressure * number of generations * ability to pass material to next generation = adaptation This is the same reason that the optimal strategy to use antibiotics is to avoid using them but when you need to, use a lot of it to make sure you kill completely whatever bacteria it is supposed to kill. By not vaccinating thoroughly and keeping regime until the virus is largely gone we are giving it right conditions to keep adapting. We are not going to get rid of this pandemic until everybody gets vaccinated or gets sick.
- ReadEvalPost 5y ago
  Animals are host reservoirs for COVID as well, meaning the fantasy of 100% vaccine coverage also does not solve the problem.
  - lmilcin 5y ago
    Currently, the virus has access to hundreds of millions of people. If the virus was restricted to animals, there would be relatively small population of people that had access to those vulnerable animals. Remember, less people sick == less chance to evolve.
- joe_the_user 5y ago
  "Whatever we do, if we do not do it decisively, we just give the virus occasion to adapt." Put it in past tense. "What we (the human race) did, since we didn't do it decisively, gave the virus occasion to adapt..."
  - lmilcin 5y ago
    No, we are still giving it a chance to evolve and we are still able to stop it.
belter 5y ago
"Andrew F. Read ,Susan J. Baigent,Claire Powers,Lydia B. Kgosana,Luke Blackwell,Lorraine P. Smith,David A. Kennedy,Stephen W. Walkden-Brown,Venugopal K. Nair" These are the names of the 9 highly respect researchers who authored the paper. This a post non editorialized and as factual as it can be. Why is it flagged?

90 points by jules-jules 5y ago

mdeck_ 5y ago

Needs a (2015) in the title.

rgbbtc4life 5y ago

This is the point in the story where all the vax naxis eat crow. Better luck next time, enjoy your ade.

JohnJamesRambo 5y ago

>Our data show that anti-disease vaccines that do not prevent transmission can create conditions that promote the emergence of pathogen strains… This isn’t remotely what we are dealing with with regard to Covid vaccination. In fact the opposite. That’s my understanding of it.

a41cf 5y ago
> this isn't remotely what we're dealing with Citation needed. More and more evidence is emerging that the vaccinated that get infected can spread it. Worse yet a so-called "breakthrough" can be asymptomatic [0]. There's still research to be done but this is the actual current up-to-the-minute consensus. If this is true then, not having a biology degree, I would assume that because these do not prevent spreading but rather mitigate severe illness those people who are infected and vaccinated are more likely to be responsible for transmitting it as there won't be many, or any, symptoms to signal you to quarantine/get tested. Moreover, historically there have been several leaky vaccines that have contributed to far more fit viruses. We could possibly be staring at the biggest health science flub in history. [0] https://www.jhsph.edu/covid-19/articles/new-data-on-covid-19-transmission-by-vaccinated-individuals.html https://www.jhsph.edu/covid-19/articles/new-data-on-covid-19...
slumpt_ 5y ago
Yep. Spoke with someone who worked on the Moderna vaccine about this. The short of it is, the window in which the virus can / has an opportunity to mutate is shortened by the vaccine. Thus, vaccinated individuals may be host to mutations if they catch COVID but given fewer “dice rolls” - if you want to call it that - would be similarly less likely to create an especially worse mutation. Couple that with the reduction of spread given by vaccines, and the difference is staggering. This paper is being wildly misinterpreted and cherry-picked by people who aren’t involved in the science, or qualified to consume it.
- f6v 5y ago
  > This paper is being wildly misinterpreted and cherry-picked by people who aren’t involved in the science, or qualified to consume it. These days everyone is a vaccine expert and climate change scholar.
  - ryanobjc 5y ago
    I’m a bit concerned as to what it really says that this is front over material on hn. The short of it, is suspect a substantial sub population here are holding a variety of opinions that ultimately result in vaccine reluctantance. While the numbers aren’t so fast as to be significant to public health, I do think it forms a sort of idea laundering or affirmation by social proof. In other words people are using the reputation of hacker news for having smart people to launder and promote anti vax.
    - haswell 5y ago
      And yet, the problematic aspects of the paper are being highlighted by the readers here. Many things make it to the front page of HN because they’re interesting. That doesn’t mean that the readership is endorsing problematic viewpoints.
    - __blockcipher__ 5y ago
      Interesting you're so focused on the "vaccine hesistancy" side of the fence. Do you have any concerns about people using their prestigious degrees and credentials to frighten the population completely out of proportion with their actual risk from a pathogen, in order to persuade them to comply with top-down public health measures? It sounds a lot like you just don't like the conclusion that this classic paper leads to: that the "societal benefit" of mass vaccination with an imperfect vaccine is not nearly as clear-cut as many have been led to believe. My advice to people is to treat the vaccines as a personal risk reduction tool and little else. The only way to actually guarantee you won't infect someone you interact with, is to have acquired (and recovered from) the natural SARS-2 virus, which will build robust immunity. As far as immunity to reinfection, looking at antibodies alone, IgG levels stay seropositive for ~3.5 years: https://www.medrxiv.org/content/10.1101/2020.07.18.20156810v1.full.pdf https://www.medrxiv.org/content/10.1101/2020.07.18.20156810v... > Based on these half-life data, we estimate that the median times for IgM, IgA and IgG to become seronegative are 4.59 (IQR 4.12-5.03), 7.78 (IQR 6.71-9.16) and 42.72 (IQR 33.75-47.96) months post disease onset. > This study suggests that SARS-CoV-2 infection induces robust neutralizing and binding antibody responses in patients and that humoral immunity against SARS-CoV-2 acquired by infection may persist for a relatively long time. and furthermore once those IgG levels fade you will still have immunological memory, which lasts basically forever and allows your system to much more rapidly and effectively respond to future infection, leading you to have a much lower peak viral load, lessened symptoms (usually fully asymptomatic) and therefore a near inability to transmit the virus. For example for the 1918 flu, immunological memory has been shown to persist 60+ years later: https://www.cidrap.umn.edu/news-perspective/2008/08/researchers-find-long-lived-immunity-1918-pandemic-virus https://www.cidrap.umn.edu/news-perspective/2008/08/research...
perihelions 5y ago
Your understanding is 100% correct. Moreover, last I read about it, covid's peak viral shedding was in the pre-symptomatic or early symptomatic stage -- it's most infectious in walking, healthy-ish people. https://www.cidrap.umn.edu/news-perspective/2020/11/covid-19-most-contagious-first-5-days-illness-study-finds https://www.cidrap.umn.edu/news-perspective/2020/11/covid-19... (The submitted paper is about "highly lethal pathogens" where "host death greatly reduces transmission". That's the opening line of the abstract, and I'm baffled how anyone would link this to covid). (edit: first version had a horrific typo, /s/incorrect/correct/)
- JohnJamesRambo 5y ago
  I don't see anything in that about vaccinated people. https://www.osfhealthcare.org/blog/fully-vaccinated-less-likely-to-pass-covid-19-to-others/ https://www.osfhealthcare.org/blog/fully-vaccinated-less-lik... >“We do not have conclusive proof. But more and more studies and real-world evidence points to fully vaccinated people, who are not immunocompromised, are less likely to transmit the virus if they become infected,”
  - perihelions 5y ago
    I've edited my comment (there was a horrific typo) -- I 100% agree with you. Covid is *not* disease like Ebola, whose transmission is self-limiting by its lethality -- it's the opposite.
    - __blockcipher__ 5y ago
      It's not as simple as lethality. Generally a pathogen needs to cause some sort of symptom in the host to spread well, but the more severe the symptoms the more aggressively the person would isolate. Insofar as the vaccines mostly worked upon their initial release, you can imagine a new strain that is much more virulent (replicates significantly faster, etc); such a strain could cause a vaccinated individual who would normally be completely asymptomatic and therefore not infectious [hopefully we all accept by now that there is pre-symptomatic spread but not asymptomatic spread, if not you're behind a year on the research], to become symptomatic and therefore capable of transmitting. If that same strain were to infected an unvaccinated individual who had never been exposed to the real virus, it might cause much more severe symptoms in them. --- There's also the separate phenomenom of immune escape. The current major vaccines (mRNA and adenovirus-vector) all just make the body's own cells express (generate) the spike protein (S2 subunit), and nothing else. So specifically point mutations in the S2 subunit could allow some degree of artificial immunity evasion (it wouldn't work against those naturally infected because they were infected with whole, live-replicating virus and thus have much more diverse epitopes for their immune system to "learn" and possibly a stronger immune stimulus in the first place)

deleted 5y ago

[deleted]

dasudasu 5y ago

>Vaccines that let the hosts survive but do not prevent the spread of the pathogen relax this selection, allowing the evolution of hotter pathogens to occur. This type of vaccine is often called a leaky vaccine. When vaccines prevent transmission, as is the case for nearly all vaccines used in humans, this type of evolution towards increased virulence is blocked. But when vaccines leak, allowing at least some pathogen transmission, they could create the ecological conditions that would allow hot strains to emerge and persist. Very relevant when coupled with the Massachusetts study that showed that the vaccinated can still spread Delta with apparently very little problem. https://www.cdc.gov/mmwr/volumes/70/wr/mm7031e2.htm?s_cid=mm7031e2_w https://www.cdc.gov/mmwr/volumes/70/wr/mm7031e2.htm?s_cid=mm...

0x_rs 5y ago
I certainly hope the similarities with Marek's disease reaching 100% mortality begin and end there. What I can personally extrapolate is that allowing or even advising vaccinated people not to wear masks and distancing is rather dangerous. https://en.wikipedia.org/wiki/Marek%27s_disease#Diagnosis https://en.wikipedia.org/wiki/Marek%27s_disease#Diagnosis
- __blockcipher__ 5y ago
  Masking has never been sufficiently proven to be effective against the spread of respiratory viruses. For SARS-2 specifically we have one randomized controlled trial, DANMASK, which showed no effect of masking (note the primary endpoint was self-infection not community transmission, but self-infection is a decent proxy, and furthermore community transmission is incredibly difficult to study, which is why it is so evil to me that the public health establishment convinced people that "my mask protects you, but not me" when there's actually never been evidence that it protects others as evidenced by the utter lack of studies on that part specifically) For the pre-2020 studies, they were more or less in agreement that masks didn't help, even in healthcare workers, who tend to be better trained and more compliant with masking protocols. Indeed Macintyre et al provides strong evidence of the risks of cloth mask wearing; while this study compared cloth masking to standard practice, not no-masking, it at a minimum establishes the very real risks of cloth mask wearing: https://pubmed.ncbi.nlm.nih.gov/25903751/ https://pubmed.ncbi.nlm.nih.gov/25903751/

buu700 5y ago

Sounds similar in principle to the consequences of failing to complete a course of antibiotics.

prox 5y ago
Nope. Please read the top 2 answers in today’s askscience : https://www.reddit.com/r/askscience/comments/ozh9mi/is_the_delta_variant_a_result_of_covid_evolving/ https://www.reddit.com/r/askscience/comments/ozh9mi/is_the_d...
- xdennis 5y ago
  A subreddit that's full of [deleted] isn't trustworthy. Unlike HN, non-admins can downvote posts they don't agree with on Reddit. A subreddit full of [deleted] indicates it's one sided.
  - prox 5y ago
    Normally perhaps. But this is askscience, which just has a high standards when it comes to answers.
    - smaryjerry 5y ago
      I’m not sure about askscience but the “science” Subreddit is completely partisan and non ruled. And the science is still changing, delta is brand new. These vaccines weren’t made for Delta at all and aren’t stopping transmission, however they do offer protection from symptomatic disease, per the CDCs own documents and new recommendation that vaccinated wear masks indoors. Per this Washington post aritcle 75 percent of new cases in highly vaccinated Singapore are in already vaccinated people, similar to the unpublished CdC internal data which made the CDC revise their mask recommendation. https://www.washingtonpost.com/health/2021/07/29/cdc-mask-guidance/ https://www.washingtonpost.com/health/2021/07/29/cdc-mask-gu...
  - jdavis703 5y ago
    Users with enough Karma are allowed to downvote on HN. That’s what the gray replies are.

thedream 5y ago

Another thing that Can Enhance the Transmission of Highly Virulent Pathogens: letting 399 unwitting human beings carry Syphilis for years while you treat them like lab rats[1]. [1] https://www.cdc.gov/tuskegee/timeline.htm https://www.cdc.gov/tuskegee/timeline.htm

nathanfig 5y ago

> Conventional wisdom is that natural selection will remove highly lethal pathogens if host death greatly reduces transmission. Vaccines that keep hosts alive but still allow transmission could thus allow very virulent strains to circulate in a population. Host death does not stop transmission of Covid-19 so I do not think this study is particularly relevant, if we’re reading it in that context.

jhgb 5y ago
But perhaps partial vaccination has a similar effect if you make transmission less likely and now only more transmissible mutations make the cut.
- noduerme 5y ago
  This is true, and I wonder whether partial vaccination didn't play a role in the rise of Delta. But more transmissible != more lethal.
  - jhgb 5y ago
    In the case of Delta it almost certainly didn't. But the fact that something happened through one mechanism doesn't mean that it can't happen through another mechanism.
- sweetdreamerit 5y ago
  Am I wrong if I think that the most transmissible mutations tend to win the competition towards the less contagious ones in any case?
__blockcipher__ 5y ago
> Host death does not stop transmission of Covid-19 Huh? It does for that host. Yeah their corpse can still spread it for awhile or whatever but they're no longer engaging in society.
- jdavis703 5y ago

purple_ferret 5y ago

I know this is making the rounds of the 'covid vaccine bad'[0] crowd, but isn't it the case that the yearly flu vaccine doesn't guarantee immunity? How has such a vaccine been flying by with such a potential danger present? [0]https://youtu.be/tiwsv51Il4k?t=98 https://youtu.be/tiwsv51Il4k?t=98

thisiscorrect 5y ago
What fraction of people take the annual flu vaccine?
- djrogers 5y ago
  That’s a pretty straightforward question to find the answer to - it’s just a bit under half, whith kids and seniors being more likely to get it. [1] https://usafacts.org/articles/how-many-americans-get-flu-shots-vaccine-cdc/ https://usafacts.org/articles/how-many-americans-get-flu-sho...
curmudgeon22 5y ago
I don't believe it's a matter of 100% guarantee of immunity. The current covid vaccines are designed to prevent severe infection, NOT prevent infection. My understanding is that the current vaccines ~95% efficacy is against severe infection, but we don't actually know what the efficacy against infection is. If you compare this to say smallpox vaccine, it is 95% effective at preventing infections. https://www.health.ny.gov/publications/7022/ https://www.health.ny.gov/publications/7022/
- krona 5y ago
  The 95% efficacy statistic was ultimately a positive PCR test, i.e. infection or a 'case' of the disease.
  - curmudgeon22 5y ago
    Yes, but only symptomatic folks were tested.

Rd6n6 5y ago

I have been assuming the idea of these vaccines was to buy time until a new one gets developed that also stops transmission. Ie, I assume we will all get a second vaccine one day that’s better that can have a shot at wiping Covid out, if we get really lucky and everyone takes it

thisiscorrect 5y ago
The likelihood of wiping out (as in, totally eradicating) a respiratory infection seems really low. Are there any examples of that happening in the past?
- jdavis703 5y ago
  The original SARS virus was eradicated.
  - ekianjo 5y ago
    nope it died out.

xdennis 5y ago

Why do these things keep coming out AFTER I've already taken a dose?

kleene_op 5y ago

It is not very difficult to imagine that antivaxxers would use this article as proof that vaccination was a mistake and that we should not go further. However, this bit: > Our data show that anti-disease vaccines that do not prevent transmission can create conditions that promote the emergence of pathogen strains that cause more severe disease in unvaccinated hosts. Actually makes a convincing case for anyone who did not get the vaccine to get it. Anyway, that won't convince hardcore antivaxxers, so we shall see in the upcoming months/years whether this article actually transposes to our situation. Just a shame this may be happening at the expense of gullible yet still good at heart people.

thisiscorrect 5y ago
The rub is that there are a lot of people on Earth. And, early evidence _might_ suggest that the vaccines that are available lose effectiveness sooner than originally thought. For example, [1] shows evidence of diminished effectiveness after 146 days. Back to "Our data show that anti-disease vaccines that do not prevent transmission can create conditions that promote the emergence of pathogen strains that cause more severe disease in unvaccinated hosts." and whether that implies that "for anyone who did not get the vaccine to get it." This sounds like a strategy that hinges on everyone on Earth getting vaccines and frequent-enough booster shots. What if that's unachievable though? The logistics for that would be unprecedented. What are the consequences of trying but failing to do it? [1] https://www.medrxiv.org/content/10.1101/2021.08.03.21261496v1 https://www.medrxiv.org/content/10.1101/2021.08.03.21261496v...
- jacobolus 5y ago
  > lose effectiveness sooner than originally thought To be precise, have partially reduced effectiveness against transmission of a variant of the virus evolved after the creation of the vaccine, while still preventing almost all severe illness/death. Possible ways forward: (1) give people additional booster shots of the existing vaccine; (2) develop a modified vaccine booster targeted more precisely to the variant virus; (3) keep public health measures in place (e.g. requiring everyone to wear face masks indoors) so long as Re > 1. > What if that's unachievable though? It has been more or less achievable for past vaccinations. It is a logistical challenge to be sure, but modern society is certainly capable of it if it is prioritized.

mrosett 5y ago

I love this kind of stuff intellectually -- deep dives on how edge cases can produce counterintuitive results. But I'm surprised to see HN uncritically assume this is relevant to Covid [1]. This article deals with viruses that have trouble spreading because they kill the victim too quickly. That's manifestly not the case with Covid, which (when compared to really nasty things like ebola or apparently Marek's) kills a relatively low share of its victims and isn't particularly quick about it. [1] Or at least the top two top-level comments do as I'm writing this.

__blockcipher__ 5y ago

For those decrying the fact that this study is about a highly deadly virus, note that mathematically speaking, the same effect would be expected to be observed for a much less obviously lethal virus, if the effect were occurring across billions of hosts, such as what we're currently pushing for globally with the mass COVID vaccination campaign

lmilcin 5y ago

It is all very simple really. Whatever we do, if we do not do it decisively, we just give the virus occasion to adapt. population of hosts * selection pressure * number of generations * ability to pass material to next generation = adaptation This is the same reason that the optimal strategy to use antibiotics is to avoid using them but when you need to, use a lot of it to make sure you kill completely whatever bacteria it is supposed to kill. By not vaccinating thoroughly and keeping regime until the virus is largely gone we are giving it right conditions to keep adapting. We are not going to get rid of this pandemic until everybody gets vaccinated or gets sick.

ReadEvalPost 5y ago
Animals are host reservoirs for COVID as well, meaning the fantasy of 100% vaccine coverage also does not solve the problem.
- lmilcin 5y ago
  Currently, the virus has access to hundreds of millions of people. If the virus was restricted to animals, there would be relatively small population of people that had access to those vulnerable animals. Remember, less people sick == less chance to evolve.
joe_the_user 5y ago
"Whatever we do, if we do not do it decisively, we just give the virus occasion to adapt." Put it in past tense. "What we (the human race) did, since we didn't do it decisively, gave the virus occasion to adapt..."
- lmilcin 5y ago
  No, we are still giving it a chance to evolve and we are still able to stop it.

belter 5y ago

"Andrew F. Read ,Susan J. Baigent,Claire Powers,Lydia B. Kgosana,Luke Blackwell,Lorraine P. Smith,David A. Kennedy,Stephen W. Walkden-Brown,Venugopal K. Nair" These are the names of the 9 highly respect researchers who authored the paper. This a post non editorialized and as factual as it can be. Why is it flagged?