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Comment by claudeganon | Hacker News Reader

All this talk of herd immunity is not terribly helpful because we don’t know what “immunity” means in practical terms.

The duration of immunity for other corinaviruses varies quite a bit, the disease has the potential to cause permanent respiratory damage, with uncertain consequences for the possibility of reinfection, and we’re still seeing novel symptoms arise as in the case of the children with Kawasaki-like inflammation in NYC.

I get the strong desire to return to a normal state of affairs, but paving over reality with scientific notions, deployed pseudoscientifically, does very little to get us there.

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We know that the vast majority of people will recover fully, and after they recover they'll be immune for a long time. Media reports have severely overstated the uncertainty here; if coronavirus can indeed trigger Kawasaki syndrome, it's only in the same sense that acetaminophen can cause liver damage.

> We know that the vast majority of people will recover fully, and after they recover they'll be immune for a long time.

How do we “know” either of those facts? You may well be right, but I don’t see a scientific consensus yet.

A combination of animal studies, observation of recovered patients, and some studies directly on the antibodies recovered patients produce. In the US at least, public health authorities have consistently said from the start that there's substantial long-lasting immunity.

This is not in anyway true and I’m not sure why you’re suggesting it is. Dr. Deborah Birx has said expressly that we don’t know the duration of immunity and initial reviews suggest immunity might not last as long as we’d hoped:

https://www.technologyreview.com/2020/04/27/1000569/how-long...

This article is discussing the hope that immunity lasts forever, and I agree there's no reason to believe that. The important question is whether it's shorter than a year or two - we're developing other strategies to handle the virus on timescales beyond that.

> This article is discussing the hope that immunity lasts forever

Nowhere is this stated or suggested. Why are you saying that it is? The only point it makes (contrary to all your claims) is we don’t know the duration of immunity and the situation is unpredictable, based on what we know of other coronaviruses. From the article:

>What I have been telling everyone—and no one believes me, but it’s true—is we get coronaviruses every winter even though we’re seroconverted,” says Matthew Frieman, who studies the virus family at the University of Maryland. That is, even though most people have previously developed antibodies to them, they get the viruses again. “We really don’t understand whether it is a change in the virus over time or antibodies that don’t protect from infection,” he says.

> After testing different scenarios, the Harvard group concluded that their projections of how many people end up getting covid-19 in the coming years depended “most crucially” on “the extent of population immunity, whether immunity wanes, and at what rate.” In other words, the critical factor in projecting the path of the outbreak is also a total unknown.

I've seen very different information on how long "for a long time" is. Even just writing "for a long time" makes me wonder, if you have a range, why not give it?

The figure for immunity duration at say 95th percentile seems to be the key figure for herd immunity being viable or not, at least to my layman eyes.

It's hard to put a concrete number on how long immunity lasts, because immunity isn't a binary process. All the experts I've seen discuss the issue have said we can expect recovered people won't catch it again this calendar year.

That's just speculation because no one has had the virus for a year.

Please stop adding certainty where it is unwarranted. Either supply citations to expert authorities, or be quiet. Otherwise you're just spreading misinformation.

Wouldn't this kind of reasoning apply to every new virus, including new flu viruses that pop up routinely? A new virus pops up and appears to be just a routine flu, but technically we can't know about its long term side effects until many years later. So why don't we apply this same reasoning and lock everything down routinely whenever any new flu virus arises?

It seems to me that you're right, we can't know for certain until many years later, but in the meantime the world goes on, we can't all just cryogenically freeze ourselves. The best we can do is make educated guesses based on previously existing coronaviruses.

I don't think they do have a range. I saw a slide a month or so ago that showed how long antibodies last for various viruses, and the range was something like 3 months to life. We simply have no idea how long SARS-CoV-2 antibodies will last.

Respectfully, these are just your suppositions, unless you have some evidence to the contrary. In every case I cited, there is no scientific consensus about what’s actually happening.

I’m not sure why people can’t seem to fathom that we are still very early in our understanding and experience of this disease, no matter how dramatic its consequences thus far. There’s no way to accelerate things through false confidence or other forms of denialism.

As I've discussed elsewhere, there is indeed evidence to the contrary.

There's also no way to decelerate things through false humility. We're in an urgent crisis, so we must make decisions now based on whatever evidence is available; there's no position of safety we can retreat to while waiting to learn more.

So provide a sliver of this evidence. You keep alluding to it, but your story doesn’t correspond to the CDC’s own statements, nor the initial review of coronavirus immunity durations I linked.

What kind of evidence are you looking for? I can point you to public health authorities saying immunity works and lasts for ~a year [1][2], but I suspect you've seen these statements already. If you're looking for a scientific study unambiguously proving it, we of course won't be able to have that until a year has passed.

[1] https://www.businessinsider.com/coronavirus-fauci-those-who-...

[2] https://www.bbc.com/news/health-52446965

- Bayesian interpretation would use what we do know about viruses in general, coronavirus specifically, anD sars/Mers as the prior.

Has anyone here done the research that we can use as a reasonable prior? My assumption was those diseases all produce long lasting antibodies.

An initial review of immunity/reinfections with coronaviruses suggests we shouldn’t be optimistic about the duration of immunity:

https://www.technologyreview.com/2020/04/27/1000569/how-long...

Disappointing to see comments like this (and many others on this site) downvoted. There is nothing wrong with this comment, it's not offensive or shrill. If someone has an issue with the logic they should reply to it.

You're right, but it's getting downvoted because it has the same basic shape as the "people aren't creating antibodies and can get reinfected" doomer meme which is making the rounds.

Also, FWIW, if getting the actual disease doesn't generate sufficient antibodies to confer immunity, being dosed with a vaccine wouldn't either. Whether vaccine-supported or not, herd immunity is the most likely outcome (unless the disease becomes endemic instead). What remains to be seen is how many people have to get ill to get there.

I simply read it as legitimately asking how long immunity lasts. I think this is a good question, not "doomer".

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