Generally speaking:
But then you have to keep containing it right?
There's not a magical end of containing unless the virus just goes away / a vaccine is available ... that doesn't seem to be a thing yet.
I'm not all for just letting the chips fall where they may, but success at preventing exposure to your population vs heard immunity means the folks who haven't been exposed have to keep avoiding it.
If you don't have herd immunity, then you need to be continually surveilling for it, and when it's present, switch to containment.
Containment is easier when the number of cases is small though. If you get a handful of cases, contact trace and make general advisory news releases. If you get more than 20 cases, ask people to wear masks. If it gets worse, then you have to take bigger steps.
America's strategy (or lack thereof) is simply negligence.
Memory T-Cell reactivity to SARS-1 has been shown to persist across decades. The latest study showed strong activity after 17+ years.
SARS-2 is incredibly structurally similar to SARS-1.
Even if we pretend t-cells don’t exist, immunological memory is a thing. Once circulating antibodies have completely faded after months, there still remain memory b cells which persist across decades and will ramp up antibody production all over again when exposed to SARS-CoV-2. Therefore the subsequent infection is addressed more quickly and more powerfully, leading to lower peak viral load and therefore theoretically lowered transmissibility and vastly improved individual outcomes.
So if we pretend half the immune system doesn’t exist, then you can get reinfected months later but you will spread way less and not be at any significant personal risk of bad outcome.
Herd immunity works. It’s a natural phenomenon that has been unjustifiably demonized.
What you are referring to is eradication, which has only ever been performed twice. SARS-2 is functionally impossible to eradicate due to its zoonotic origin and incredible spread.
Even with herd immunity SARS-2 is here to stay. That’s not a problem though, even if we could so something about it. Why? Because SARS-2 kills the very old but spares the very young. Therefore once it has passed through the current population, the set of SARS-CoV-2-naive individuals becomes dominated by new entrants to the world, meaning babies/toddlers, the same group that does not die to COVID-19 in any real numbers. Therefore unlike Influenza, recurring deaths from COVID-19 will be incredibly low in subsequent years.
Why would you willfully ignore the enormous research literature showing enduring immunity developing from SARS-1? Oh, right, because either you haven't read it or you don't like that it doesn't support your conclusions.
It's like, imagine we're discussing H1N1 reinfection, and we have a highly similar H1N0 which varies very slightly, and we know that doesn't lead to reinfection. But instead you look at a number of Influenza viruses in the same family but not nearly as similar.
Don't you see how ridiculous that is?
We obviously should use SARS-1 as a model for SARS-2.
Basing an entire countries policies around a supposition that herd immunity is practical is, in my opinion, negligence. It's only practical for diseases that don't kill 0.5-1% of the infected population.
It's been proven that lockdowns and slow reopenings work to limit spread, followed by contact tracing clusters to prevent reemergence until community vaccination programs.
Americans are just bitter that their governments are totally inept.
What is it about SARS-2 that makes it so that a few hundred thousand dead is impractical and negligent?
(BTW, the hidden argument of yours here is that we can successfully avoid that mortality by practicing containment which I dispute)
Practicing containment is like leaving a forest full of extremely dry brush. It works great until the fire starts.
We should be assuming that immunity doens't last long and basing all policies on that assumption until proven otherwise.
I wasn't encouraging infecting everyone intentionally.
I was noting the ongoing scale of effort required to protect everyone you keep a large % of the population unexposed.
>We should be assuming that immunity doens't last long and basing all policies on that assumption until proven otherwise.
I don't think that assumption makes sense at all with modern medical science.
In a risk-benefit analysis, it leaves future (speculative) advances in treatment VS acquiring herd immunity as quickly as possible and with minimal actual damage, for this it makes sense to maximize exposure for the less at risk.
Also, the summer is a better season to get infected, at least because of generally better immune system function (because of better vitamin d status).
Anyway to state your excellent point in a different way: “contain until vaccine” is a strategy based around a temporally unbounded future event. When has it ever made sense to bet the farm on a highly uncertain future event?
This world would be so much better off if we never knew that SARS-2 existed and therefore did not engage in any artificial suppression of natural transmission.
Even a modest degree of immunity can significantly lower spread. In France, Spain, Germany, you still have hundreds of cases every day, but they don't grow to thousands of cases anymore.
The disease hasn’t been around long enough to make this claim.
> Even a modest degree of immunity can significantly lower spread. In France, Spain, Germany, you still have hundreds of cases every day, but they don't grow to thousands of cases anymore.
This is true, but depends on the duration of immunity and a more uniform global response (or very tight border and quarantine adherence). Ongoing, sporadic COVID crises would still be pretty disruptive unless we have highly effective therapeutics.
So where are they? Are you claiming that these hundreds of confirmed reinfections simply haven't been reported? Note that the number of actual reinfections would be orders of magnitude higher; the calculation above already assumes underascertainment by a factor of ~100x. You can redo this math in any moderately hard-hit region, though I chose Sweden here because their rate of infections vs. time has been more constant (eliminating the possibility that all the infections happened in a brief early peak, after which everyone acted more carefully so there's no longer any opportunity for reinfection). I'm not saying that reinfection is impossible, just that so far, if it exists, it's very rare.
And please don't cite the Vox article. In normal times, it would be criticized as "science by press release" or worse, a single anecdotal case written up as definitive for the popular press, with no case history and no publication to review. Maybe the author's patient really did get reinfected and it's common (but that seems vanishingly unlikely to me per above), or maybe the patient was reinfected but it's rare like getting chickenpox twice, or maybe the patient just had one long infection and tested false-negative (which is very common generally) in the middle. But since the author has disclosed nothing but the shocking headline result, we can't know.
So I believe you are sowing public panic without evidence. While it is impossible to directly demonstrate that immunity for a disease discovered X months ago lasts longer than X months, it is reasonable to expect that in this case. Maybe you think that at worst, if you're wrong, then you're telling a noble lie--but the public health authorities who said masks don't work (remember that?) did too, and look how that ended up. I can easily imagine Trump on television a year from now explaining that because people got reinfected, the vaccine is obviously a scam.
Abandoning the truth in favor of a perceived noble goal has unpredictable but generally bad effects, and I wish people would stop. Or if you actually believe what you're writing, I'm not sure what to say--please read the scientific literature (and not the popular media, which has been horrible in all directions), dust off your high school biology, and make your best assessment based on that. I think you'll find that while the coronavirus is a very serious problem, it's not the near-apocalyptic one that your comments seem to imply.
https://www.sfchronicle.com/health/article/With-coronavirus-...
https://www.medrxiv.org/content/10.1101/2020.07.09.20148429v...
Likewise, asymptomatic cases appear to have limited immune duration and development:
https://www.jci.org/articles/view/138759#ABS
And meaningful immunity might depend on how much of the virus one is exposed to:
https://www.nature.com/articles/s41591-020-0965-6
I linked to the Vox article because it covers a lot of bases in disputing the spurious narratives that have circulated in places like the US, where the disease is out of control, pandemic response is poor, and various forms of denialism are used to excuse all of this. I don't think its an apocalyptic scenario for humanity writ large, but certainly a dangerous one for many countries, especially if an ongoing, effective public health response is required.
>While it is impossible to directly demonstrate that immunity for a disease discovered X months ago lasts longer than X months, it is reasonable to expect that in this case.
Instead of attributing motives to other people, perhaps interrogate your own need to insist on statements like this, absent any evidence, as well as the tone of your broader rebuttal. I have no intention of sowing panic or engaging in "noble lies," but nor will I embrace evidence-free narratives to soothe myself or others.
If the US intervened early or effectively with measures like those in Taiwan or South Korea, we would likely have the situation under control. It's still possible that we could do this and I hope that we do.
I also agree that whatever immunity patients get after a mild or asymptomatic case is likely to be weaker than after a severe case. That's one case where my calculation above could be wrong--if there are many reinfections but the first or second case is always very mild, we might be much more likely to miss those. That would still be good news for the patients, though bad news for the overall population if they're still comparably infectious.
Finally, even if a patient's immunity degrades to the point they no longer exhibit sterilizing immunity (i.e., the virus still replicates a little at first), in most diseases they won't get as sick as the first time. So even if the coronavirus becomes endemic (which seems relatively likely, since many countries will lack the resources to eradicate it even with a vaccine), I expect the cost in mortality from whatever reinfections do occur to be far lower than what we're seeing now. The opposite of that (antibody-dependent enhancement) does occur, and was a specific concern here because vaccine studies for the original SARS showed evidence of that. So far vaccine studies for SARS-CoV-2 do not, though.
I actually thought the SF Chronicle article wasn't terrible, more pessimistic in its conclusions and tone than I would be given the same evidence but with many of the points above. Their headline seems irresponsible to me though; even if durable sterilizing immunity were impossible, a vaccine that cut the IFR by a factor of ten would be tremendously valuable to the elderly. All that nuance is lost when people just say "reinfection is possible". I was probably too strong to say "sowing public panic", but I do believe your comments paint a falsely pessimistic picture of the current science, and that this false pessimism can be harmful later (e.g., by causing people not to seek a vaccine because of something they half-understood about immunity). Specifically, I also believe the absence of confirmed reinfections out of places like Sweden is strong evidence that immunity usually lasts >3 months. If you were claiming that reinfection might be common after a year, then I'd be much less sure (though I'd still guess probably not based on the original SARS).
In any case, I certainly agree that younger people shouldn't get themselves deliberately infected in search of whatever immunity that affords (though the death rate among young people is low enough that I doubt reinfection would change the calculus for anyone considering that either way). I also agree that the USA response has been terrible, and resulted in a lot of avoidable death--I'm not sure, but it seems possible to me that just with universal mask use and good hygiene (like in Japan), we could live otherwise normal life with negligible spread.
ETA: And here's a paper showing neutralizing antibodies for at least three months (the limit of the study, which they're continuing) in New York. It seems beyond any reasonable doubt to me that immunity lasts three months, and I believe you're simply wrong to question that. Longer gets more speculative, but I think it's quite likely.
https://www.medrxiv.org/content/10.1101/2020.07.14.20151126v...
Also, if I understand correctly, it has recently been shown that people who were infected with SARS 17 years ago still have memory T cells for SARS. (And, I think SARS is one of the viruses most closely related to Covid-19, and therefore there's reason to expect a long immunity period for it too).
"Memory T cells induced by previous pathogens can shape the susceptibility to, and clinical severity of, subsequent infections. <snip> We then showed that SARS-recovered patients (n=23) still possess long-lasting memory T cells reactive to SARS-NP 17 years after the 2003 outbreak." - from https://www.nature.com/articles/s41586-020-2550-z
https://www.vox.com/2020/7/12/21321653/getting-covid-19-twic...
https://www.theguardian.com/world/2020/jul/12/immunity-to-co...
The idea of reinfection contradicts decades of well established immunological principles. It also ignores the fact that we have a close relative of SARS-2 to study. That relative is SARS-1 and we have detected strong t cell activation after 17+ years. Therefore immunity is enduring and long lasting.
SARS-2 is substantially structurally similar to SARS-1.
Alternatively, take a statistical argument. There have been millions of cases around the world. SARS-2 is highly infectious for those who are susceptible. Therefore we would have thousands if not more well-documented, inarguable cases of reinfection. We don’t have those. All we have is a bunch of articles from heavily biased sources like Vox that have a vested interest in pushing the “doomer” narrative.
Why haven’t we seen widespread reinfection if it is truly possible?
https://www.sfchronicle.com/health/article/With-coronavirus-...
https://www.medrxiv.org/content/10.1101/2020.07.09.20148429v....
Likewise, asymptomatic cases appear to have limited immune duration and development:
https://www.jci.org/articles/view/138759#ABS
And meaningful immunity might depend on how much of the virus one is exposed to:
https://www.nature.com/articles/s41591-020-0965-6
If this research holds up, we'll have your well documented cases in probably 3-6 months. Frontline doctors, outside the one cited in the Vox article, are already insisting its true.
Even though they wane, memory b cells persist, meaning subsequent infection is milder and theoretically less transmissible.
Additionally that reinfection potential only exists if you ignore t-cells. When you factor in t-cells, it simply does not happen.
We're in July 2020. SARS-2 existed since some point in 2019, probably midway through. Granted we couldn't detect reinfection until the whole globe had been freaking out about it, so let's start our clock from January 2020.
It's been 6 months and we don't have dozens of well-documented, credible reinfections?
No, such one-off supposed reinfections are much more explainable from a bayesian perspective of either false positives or false negatives of PCR.
Find me someone who is not immunocompromised, who is PCR-positive for SARS-2 and from whom viable SARS-2 is successfully cultured, then show them fighting off the infection and being PCR-negative and symptom-free for weeks, then show me them being PCR-positive again with viable SARS-2 cultured from their body. That's the standard.
20 examples of that and reinfection definitely happens. Until then, our priors are that we should assume it does not.
Such fears are just used to argue against herd immunity, which has been made into a "dirty word" (phrase). Herd immunity is a natural phenomenom, arguing "against" it is like arguing against natural selection in my book. (The analogy is not perfect but I hope you see the point. I'm tired of being called callous for saying "hey let's not fuck with the normal population immunity dynamics that we've used for every other highly infectious virus in existence")
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BTW, I can't find the study but they have tested reinfection in primates and showed them unable to get reinfected
>Sustained IgG levels were maintained for more than 2 years after SARS-CoV infection. Antibody responses in individuals with laboratory-confirmed MERS-CoV infection lasted for at least 34 months after the outbreak. Recently, several studies characterizing adaptive immune responses to SARS-CoV-2 infection have reported that most COVID-19 convalescent individuals have detectable neutralizing antibodies, which correlate with the numbers of virus-specific T cells. In this study, we observed that IgG levels and neutralizing antibodies in a high proportion of individuals who recovered from SARS-CoV-2 infection start to decrease within 2–3 months after infection. In another analysis of the dynamics of neutralizing antibody titers in eight convalescent patients with COVID-19, four patients showed decreased neutralizing antibodies approximately 6–7 weeks after illness onset. One mathematical model also suggests a short duration of immunity after SARS-CoV-2 infection. Together, these data might indicate the risks of using COVID-19 ‘immunity passports’ and support the prolongation of public health interventions, including social distancing, hygiene, isolation of high-risk groups and widespread testing.
So the rate of decrease is already greater than SARS and MERS under this initial investigation. I agree that we don't know the rate or duration of immunity, but nothing so far seems to point in the direction you keep emphasizing or justifies your confidence. I actually do hope immunity ends up being longer lasting, but what I "hope" is irrelevant.
I don't know that herd immunity is a dirty word, but might, for COVID, be being deployed dangerously and pseudo-scientifically. The "natural phenomenon" you refer to does not occur in all cases for all diseases. It's not callousness unless you're explicitly denying that reality and justifying excess death and illness on a dynamic which may not even be in play.
What's an example of an infectious disease that the body can fight off that does not result in herd immunity? (so, herpes and aids don't count because the body doesn't fight them off whereas we KNOW that the body fights off SARS-like diseases)
As far as reinfection is concerned, T-cells are more relevant. I am aware that antibody response fades sooner for SARS-CoV-2.
("SARS-CoV-2-specific T cell immunity in cases of COVID-19 and SARS, and uninfected controls")[https://www.nature.com/articles/s41586-020-2550-z] - Published: 15 July 2020
* Here, we first studied T cell responses to structural (nucleocapsid protein, NP) and non-structural (NSP-7 and NSP13 of ORF1) regions of SARS-CoV-2 in COVID-19 convalescents (n=36). In all of them we demonstrated the presence of CD4 and CD8 T cells recognizing multiple regions of the NP protein. We then showed that SARS-recovered patients (n=23) still possess long-lasting memory T cells reactive to SARS-NP 17 years after the 2003 outbreak, which displayed robust cross-reactivity to SARS-CoV-2 NP.
* Surprisingly, we also frequently detected SARS-CoV-2 specific T cells in individuals with no history of SARS, COVID-19 or contact with SARS/COVID-19 patients (n=37)
> It's not callousness unless you're explicitly denying that reality and justifying excess death and illness on a dynamic which may not even be in play.
Again, the excess death is the deaths caused by lockdown, not the deaths caused by a highly infectious respiratory virus. All highly infectious respiratory viruses are dealt with the same way: acquiring population immunity. Vaccines are just a way to achieve that more cheaply, but because we do not currently have a vaccine it does not make sense to try to "stop, drop and roll" until we have one. Especially because, speaking for the US, we are on track to hit population immunity before we ever get one.
At the point that you're making blatantly counterfactual statements like this, it's hard to take anything else you say seriously. Some estimates put excess deaths from things besides COVID during lockdowns at about 35% to the total, but they in no way exceed the excess COVID deaths themselves, especially given the likelihood of COVID death undercounts.
You also obviously don't understand how the thresholds for herd immunity work are dependent on duration of immunity and social dynamics of populations. All of humanity doesn't just get together and say "let's get together, right now, and see which of us dies," as much as you would seemingly like to argue that they should. We don't have herd immunity to any number of diseases (e.g. cholera) because we quash their spread through other means, like sanitation, quarantines, using masks. I don’t know why you cite SARS over and over again without acknowledging that we don’t have herd immunity or a vaccine for it.
I wasn’t talking about “excess deaths” ie the extra deaths not explainable by known covid deaths. Sorry for the confusion. (Although I think more of those deaths are non-covid, likely cardiac disease etc due to fear of hospital)
(2) I talk about sars-1 because covid is caused by sars-2. You understand that right?
We don’t have herd immunity to sars-1 because it burned itself out. Sars-2 will not do that because it is not nearly as lethal and exhibits presymptomatic spread. It is here to stay.
Also by pointing out we don’t have a vaccine for sars-1 that only strengthens my argument that banking on a vaccine for sars-2 is foolish
As far as coronaviruses go, there are four mild human coronaviruses that are responsible for about 15% of common colds and for which humans do not develop any long lasting immunity.
There are also the three severe human coronaviruses: MERS, SARS-CoV, and SARS-CoV-2. AFAIU, long-lasting immunity to these is not well understood.
I do not understand how you can make such an authoritative statement about re-infection risk based on the limited data we have about SARS-CoV-2. Here's what immunologists have to say:
> In summary, progress since January 2020 has been impressive, but there is still so much more to learn. Are T cells protective and if so which are the key antigens and and cytokine effector programs to focus on? Are all T cell responses beneficial, or are some contributory to immunopathology and to be avoided? If it is indeed the case that antibodies are transient and T cell memory is more durable (though, how durable?), what can we learn about anomalies of T follicular helper-B cell interactions in germinal centers? In the short to medium term, we need to ensure that all of this T cell toolkit and knowledge is brought to bear on robust, comparative evaluation of the different vaccine platforms, their immunogenicity, efficacy and safety. Entering the next part of the battle, there are many thousands of people suffering the chronic aftermath of infection posed by chronic, so-called ‘long-COVID’ cases, characterized by diverse symptoms including fatigue, joint pain and dyspnea (19). A more detailed understanding of the T cell immunology will be valuable in deciphering this pathogenesis.
https://immunology.sciencemag.org/content/5/49/eabd6160.full
What I read there is a lot of "we're not sure yet."
At a minimum, we can agree that in the event of re-infection, the subsequent infection will hit a lower peak viral load and therefore theoretically a much milder outcome with reduced transmissibility, right? This is called immunological memory and arises due to memory b cells and memory t cells which persist across decades.
Anyway, please see https://www.nature.com/articles/s41586-020-2550-z
It establishes that those exposed to SARS-1, which structurally and functionally is incredibly similar to SARS-2 and thus is our best model of how to think about SARS-2, have long-lasting immunity. Their t-cells not only react to SARS-1 after 17 years, they also have immunity to SARS-2, which is a testament to how similar they are structurally speaking.
Additionally exposure to those common cold human coronaviruses you mentioned almost certainly confers immunity to SARS-2 based off that same paper. We're still hashing out the details, of course.
Immunology is incredibly complex and there is still plenty to learn about as far as the exact specifics of what unfolds here, yes. But we should assume reinfection isn't possible, because:
- It doesn't happen in SARS-1 which is by far the best model we have
- If it did happen, given the MILLIONS of cases of COVID-19 worldwide, we would have seen THOUSANDS of rigorously documented examples of the phenomenom happening
- Those arguing for reinfection tend to not make any mention of immunological memory
- Those arguing for reinfection do so to in an attempt to scare us into staying locked down until "the vaccine", which I am opposed to because I am opposed to any public health policy that banks on a future technological innovation that does not yet exist, particularly when I fear that the environment of irrational fear and anxiety and outright hysteria is going to be used to mandate vaccines, which is highly unethical under my moral framework
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As far as me sounding over-certain, frankly it's cognitive draining to be arguing against a horde of people whose priors have been completely screwed up by programming from a media that takes delight in knowingly lying to citizens, and even our trusted public health officials like Fauci don't have the courage or perhaps the desire to break out of the collective mass delusion we are all trapped in.
So yes, if I had infinite time and energy I agree, I could do a way better job of capturing uncertainty. I've written an 8000+ word writeup on COVID that does a much better job capturing the uncertainty, but it's very difficult to do without...writing 8000 words.
Also this doesn't justify it but I do feel the need to point out that those arguing for the "doom" scenario are even more egregiously overstating certainty, and tend to not be called out on their ridiculous statements. So that's why I tend to come into these threads guns blazing, with the predictable result of getting hammered by downvotes. C'est la vie.
No, they don't, or they wouldn't have new cases, even without even somewhat looser mandatory controls than other places. What they have is some degree of immunity in the population (not herd immunity) plus (in some subset of those places) some degree of contact tracing backed by targeted mandatory, or at least voluntary, quarantines/isolation of the exposed, and (in large part because of the intense impacts each has had) voluntary general distancing.
That's not what herd immunity means.
The Herd immunity threshold is attained when the R factor drops below 1, assuming otherwise uninhibited spread. The threshold for herd immunity for COVID-19 has been estimated at 50-80%, but that is assuming an R0 that is likely overestimated.
Given that spread is still mitigated by certain interventions, and since we don't know the impact of those interventions on R, nor do we know R0, we don't know if we have herd immunity. However, we do have R below one in many European countries.
https://www.medrxiv.org/content/10.1101/2020.07.15.20154294v...
And for real some people have many more contacts than others (nurses, police, etc.). They get infected first, with disproportionate harm, but then become immune first with disproportionate benefit. That heterogeneity means 1 - 1/R0 is potentially a significant overestimate of the share of the population that needs to get infected for herd immunity, but there have been very limited efforts to quantify that so far.
It seems like some people believe natural herd immunity (from recovered patients) could work like vaccination does, to effectively eradicate the disease? That's probably false--the most likely natural endgame would be that the coronavirus becomes endemic, always present with some low incidence, with continuing mortality that's very low (because the incidence is low, and because older people probably benefit from immunity from when they were younger and the IFR for young people is <1/100 of older people's) but nonzero.
Finally, herd immunity and interventions (social distancing, masks, etc.) work together. It's possible (and likely I believe) that in hard-hit areas that now show R ~ 1, this is due to the product of both factors, and that either relaxing to their previous lifestyle or applying the same interventions in a naive (100% susceptible) population would show R > 1.
But in any case, the immunity level of the population reduces the need for other measures in order to stay below an R0 of 1.
There’s a massive spectrum of efficacy in the dozens of different suppression or containment policies that can be applied, combined with demographics and geography of the location being studied.
But in any case, the immunity level of the population is a downward force on R0 that, for example, will naturally keep daily cases lower in New York vs. Florida regardless of policy.
The case rate has dropped faster as the restrictions have eased.