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Comment by alejohausner | Hacker News Reader

In other words, when you recover from covid-19, you are immune to it. In other words, covid-19 is just like every other virus, in this respect.

Governments around the world have reacted with terror to this pandemic, but that doesn't mean the virus is some sort of strange monster. It's extremely infectious, and somewhat more lethal than influenza. That's all.

When I first heard about those patients who had recovered from the virus, and yet were still testing positive, it felt like a mistake. I'm glad it's been cleared up.

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In the interpretation of the NYS serostudy most favorable to your argument (assume perfect specificity), with 21% actually infected in NYC proper, based on the death statistics and the population of NYC, C19 appears to be a full order of magnitude more lethal than any recent flu strain. That's more than "somewhat" more lethal.

Putting this into perspective: in roughly a single month, we've already doubled the 7-year average annual number of flu deaths.

Project those C19 stats out across the whole population, and assume (generously) herd immunity effects at 70% that halt the progression, and you're looking at mortality rate that swamps that of all wars, terrorist attacks, and natural disasters faced by the US for the last 50 years, right?

Put differently, unchecked and with that extrapolated fatality rate, we'd be looking at something like 53 years worth of flu deaths at the average annual flu death rate? (Again, I'm just averaging the last 7 years for which we have flu stats; they range between ~12k-45k.)

(Happy to have my math corrected).

>Putting this into perspective: in roughly a single month, we've already doubled the 7-year average annual number of flu deaths.

I am really surprised how often I have seen "it is just the flu" type rhetoric upvoted on HN. I thought this was an intelligent, technological, scientific, and logical community. I don't see how anyone can square the idea that it is just the flu with evidence like what you posted above. COVID-19 has already accumulated a higher death toll in the US than any flu in over 40 years (I'm sure it is longer, but that is as far back as I can find data on with a quick Google search). That is all with basically the entire country under stay at home orders. There would be hundreds of thousands if not millions of deaths if we treated this like the flu.

I never said that this is "just the flu". I put some thought into my comment, and it's provoked some discussion.

Let me provoke some more: I predict that, by the end of this year, the number of total deaths in people over 85 will be about the same as last year.

I'm using the fact that most deaths from this virus occur in people who are already ill from other conditions. Frail old people are much more vulnerable to succumbing to infections.

Last year, about 13.5% of people over age 85 in the USA died [1]. That high death rate means that, at some point in the year, 13.5% of those people fell very ill, and had only months to live. This year, without the pandemic, a similar proportion of people would be close to death. If they caught the virus that causes covid-19, their death would be hastened. However, they would have died anyway, this year.

I know it's callous to say "they would have died anyway," since death is a terrible thing. However, humans have a limited lifespan, for some mysterious reason, and at some point our bodies start to betray us: we develop heart disease or cancer, and our immune systems become less effective. It's as if our bodies are lowering their defenses, almost inviting death. Often, along comes a flu, to finish the job. This year's angel of death is a different respiratory virus, not influenza.

1. https://www.cdc.gov/nchs/products/databriefs/db355.htm

According to this admittedly outdated CDC page[1], the 85+ age group makes up 30% of COVID-19 deaths. Even if you are right about that group (which I think is feasible but unlikely), there is still a huge population of people who are dying who were not previously close to dying.

[1] - https://www.cdc.gov/nchs/nvss/vsrr/covid19/index.htm

That's not an entirely fair way to slice, since only 6% of deaths in any age group are folks without comorbidities. I'll dig up the reference, pretty sure it was NYC data. We'll have to wait for the dust to settle but I'm pretty sure we're looking at an upper bound worst-case of basically everything we've measured re COVID.

I'm at a loss for why anyone should care about the fact that younger people dying have "comorbidities". If asthma or hypertension have suddenly become a death sentence, that is a very big deal; virtually every American has families with one of the "qualifying" C19 comorbidities.

It's not a death sentence by any stretch, you're substantially overreacting.

CDC data puts the US flu fatality rate at 0.1% (up to 20-60,000 deaths for 45,000,000 annual infections ~= 0.1%) and serology studies are putting COVID at around 0.3% -- not adjusting for comorbidities. So it's worse than the flu overall, but massively skewed older so for young and especially young and healthy people it's not materially different than the flu. For kids, its better than the flu -- which kills both the young and the old.

And yeah, the flu kills seemingly young and healthy people, too, we just don't really talk about it.

For old folks, it's much worse. We need to keep them safe, but that doesn't mean we need to freak out about children catching it when they're gonna be just fine. [1] Remember 99.2% of the folks who died in Italy averaged 80.5 years old with an average of 3 comorbidities. Zero health professionals under the age of 49 died in Italy despite constant and repeated exposure. [2]

Not everyone is equally affected by COVID and for the overwhelming majority (99.7% of all people), it's by no means a death sentence.

I strongly suggest you read [2] for perspective. I know all the breathless screaming on television has colored your perspective on all this, and yeah, it's not great. However, allow data to be your guide. We're gonna be just fine.

[1] https://www.wsj.com/articles/consensus-is-emerging-that-chil...

[2] https://www.cebm.net/covid-19/global-covid-19-case-fatality-...

It is weird how you are insistent on focusing in on how comorbidities impact COVID patients but ignore the same comorbidity issues for flu patients. Also not all comorbidities are created equal. I can understand the original argument if everyone dying of COVID-19 had stage 4 lung cancer, but there are people dying with chronic conditions like asthma that traditionally have little impact on life expectancy.

Also the 0.3% number you are referencing is being questioned as other serology studies have shown it to be 2x-3x higher. The reality of the situation is that we don't know the exact fatality rate of COVID-19. What we do know is that it is at least a few times more deadly than the flu and potentially an order of magnitude more deadly. We also know that the coronavirus is much more infectious than the flu. Like previously mentioned, we have already passed the worst flu numbers even while most of us are under a stay at home order. It seems like no matter how you look at the data, the only way in which COVID-19 is not worse than the flu is how it impact the very young. COVID is more deadly in basically every other way. I honestly don't see what people gain from continuing to downplay this disease in relation to the flu.

> It is weird how you are insistent on focusing in on how comorbidities impact COVID patients but ignore the same comorbidity issues for flu patients.

That's fair, although age matters way, way more, so we can elide the bit for future re-readings.

> Also the 0.3% number you are referencing is being questioned as other serology studies have shown it to be 2x-3x higher. The reality of the situation is that we don't know the exact fatality rate of COVID-19. What we do know is that it is at least a few times more deadly than the flu and potentially an order of magnitude more deadly.

I'm not just referencing the Gangelt data, but also the Vo data, and the Santa Clara data (which is very much in question now). That was also approximately the IFR for the Diamond Princess (0.85%) but of course Diamond Princess skewed much older so likely that IFR represents an upper bound. There are precious few population studies for us to reference, but they're far more valuable for making public health decisions than the ratio of people who go into a hospital as compared to come out. That only defines the numerator, without defining the denominator.

I'm also basing it on the estimates during the pandemic that H1N1 had a CFR of 0.1-5.1% from country to country, and landed on an IFR of 0.02%, or one-fifth the lowest estimate. [1]

> What we do know is that it is at least a few times more deadly than the flu and potentially an order of magnitude more deadly.

Not for all demographics. It's demonstrably less fatal for children, which the flu does not spare, and approximately the same for folks under 49.

> Like previously mentioned, we have already passed the worst flu numbers even while most of us are under a stay at home order. It seems like no matter how you look at the data, the only way in which COVID-19 is not worse than the flu is how it impact the very young. COVID is more deadly in basically every other way.

There's reasons you shouldn't compare COVID's current numbers to an average flu season. One being that COVID's new so none of us have immunity. It's also more virulent. It's affecting a similar size population but just all at once instead of spread out, so it's impact is concentrated in time. That makes it not particularly meaningful to project out. Not to mention that flu number is after a vaccine and after a lifetime of exposures, so likely doesn't represent an apples to apples comparison. If the flu vaccine is 10-60% effective, you should probably multiply the number of expected flu cases by up to 2 - or more. Think of it more like the first time someone caught the flu.

Further, the flu changes regularly, and comes back at us repeatedly, and COVID may well not -- early indications are promising in that regard.

I'm not trying to downplay anything, I'm trying to synthesize the data we do know and not fall into the panic that is dominating the discourse. We shouldn't make big decisions while scared senseless, we should allow the data to dictate as much as possible.

Saying this disease is a "death sentence" for an asthmatic 20 year old is panic. It's just not that. 17% of hospitalizations involved asthmatics in the month of March [2] while 8% of the US population has asthma. So I guess your risk is doubled. From 0.3% to 0.6% without adjusting for age. That is not a death sentence.

[1] https://www.cebm.net/covid-19/global-covid-19-case-fatality-...

[2] https://www.cdc.gov/mmwr/volumes/69/wr/mm6915e3.htm#T1_down

I'm just letting you know this is where I drop out of this debate.

You are not being consistent in your arguments. You are criticizing me for not making an apples to apples comparison and in the same paragraph you are doing exactly that by talking about all the preventive measures that reduce flu deaths while ignoring that the country is currently shutdown to prevent COVID deaths.

You are cherry picking statistics to support your point while ignoring data that conflicts with it. For example the data coming out of New York suggests a higher fatality rate and the numbers you are using from the Diamond Princess are either out of date or flat wrong.

You are both putting words in my mouth and pretending I didn't say things that I did. No one here ever said "this disease is a "death sentence" for an asthmatic 20 year old". I already admitted that the only group that has less to fear from COVID than the flu is the very young, yet you are still bringing up that point when I am talking about overall fatality rates.

> You are not being consistent in your arguments. You are criticizing me for not making an apples to apples comparison and in the same paragraph you are doing exactly that by talking about all the preventive measures that reduce flu deaths while ignoring that the country is currently shutdown to prevent COVID deaths.

Apologies, what I was trying to say is that comparing COVID now to an average flu isn't an apples to apples comparison even if the numbers land where they are now, for all those reasons, some of which are non linear. This is including the ones you mention. The flu has a vaccine, and plenty of past exposures. COVID has the shut-down -- though it also has huge virulence and asymptomatic transmissions that appear to be ongoing.

> You are cherry picking statistics to support your point while ignoring data that conflicts with it. For example the data coming out of New York suggests a higher fatality rate and the numbers you are using from the Diamond Princess are either out of date or flat wrong.

Indeed the Diamond Princess number was out of date. I'm suggesting that there's a broad spectrum of CFR estimates (0.08% to 15%) and there's reasons neither is representative.

> You are both putting words in my mouth and pretending I didn't say things that I did. No one here ever said "this disease is a "death sentence" for an asthmatic 20 year old".

GP, who I realize now is not you said: "If asthma or hypertension have suddenly become a death sentence, that is a very big deal;..."

It'll be interesting to see where the dust settles.

Speaking as the person you thought you were replying to: "younger" as in "than 85+", the context of the thread. "20 years old" is something you made up to make your argument look more sound than it is.

The 20-ish demographic is actually the worst case with respect to asthma, representing a larger than average proportion of asthma-positive COVID hospitalizations because they don't really have many other co-morbidities and they're young. It's all in the link I provided. 20-ish is actually to your advantage, not mine. I'm not trying to "win" anything, just provide some perspective.

I will just say kudos to you for admitting when you were wrong. Many people would have just ignored my comment and never responded.

Hey I don't wanna be wrong, always happy to be learn I am so I can stop ;) if my goal were to scream into the aethter there's easier places.

If you thought programmers were 'scientific and logical' you'd be dead wrong. I used to think that too but after years of experience and seeing so many cargo cult, gut feeling, lazy opinions, bad optimizing just within programming itself, you realize that as a group we are quite prone to emotional argument, lack of discipline and general laziness with argument or research on a topic.

Also: even if it was "just the flu": another flu would be a catastrophe all its own! You can still die of the flu, even in the post-C19 (or F19) world!

Not necessarily. The flu mutates substantially and often, and new subtypes keep popping up making a consistently effective vaccine elusive (flu shots are 10-60% effective each year based on our ability to guess which strains will dominate). There's no meaningful evidence indicating the same is true for COVID yet, so once we've all had it -- or a vaccine -- it could be over just like that, never to be heard from again. Unlike the flu. In the full course of time the flu may well prove to be much more dangerous.

Time will tell. Not saying one way or the other just that the worst case you've illustrated is far from a foregone conclusion.

>I am really surprised how often I have seen "it is just the flu" type rhetoric upvoted on HN

This is a unfair way to respond to [alejo's] comment. The fact that you have responded in this way to this thoughtful response suggests to me that the problem may lie in the way you are reading, understanding, and internally labeling other people's views.

This idea of putting 50 years of any war/ attacks etc is misguided and it’s a wrong use of statistics. A better approach would be to take into account other diseases as you have with its close relative the flu. Others on the list would be other types of diseases. Because all of those dwarfs numbers from wars etc.

Why is it "misguided and a wrong use of statistics"? It's true that the flu kills far more Americans than the last 50 years of war has. If a new disease emerged that was just the flu in a different form, and we retained the mortality rates both from the flu and that new disease, that alone would be extremely alarming: a new cause of death, displacing none of the other deaths, that exceeds most other causes!

Honestly, I think we don't do nearly enough comparisons between disease mortality and other causes of mortality. A "War On Cancer" would have done us far more good than the wars we declared in the 2000s would have.

Nixon signed a bill in 1972 that declared just such a "war on cancer". This war has not been won. A few cancers have been reduced, but cancer as a whole remains intractable. Most of the decline in cancer deaths over the past decades are due to fewer people smoking.

I'm not saying that wars on "terror" are a good thing. It's just that cancer is a very tough problem.

the more precise wording would be that you're comparing different time periods and then using that to extrapolate rationale. that's an error of statistical reasoning.

the more accurate exapolation would be relative to the first 4 months of every other studied emerging disease, considering the estimated errors of each of the important variables. you'd fit the various current studies on corona/covid, considering the high uncertainty as (large) estimated error, and providing a range of future outcomes with probabilities on them.

instead, you're asserting your worst possible scenario as the most likely outcome.

~~~~~~~~~~~~

now on the idea that we're entirely too blasé about preventable mortality in general, i agree. if we rigorously and intelligently attacked auto accidents, if we addressed cardiopulmonary diseases caused by pollution and poor habits, and if we regularly shut down the economy for the past decades because we want to reduce the hundreds of thousands of contagious disease fatalities every year and had the socioeconomic safety nets in place for that all along, then the current actions would seem more reasonable.

instead, the response is out of proportion with our own past actions because of panic and fear. it happened with 9/11, mass shootings, fukushima, and everything else. the herd is not good at reasoning about rare and novel mortality events.

Or traffic collisions. Not a disease, but I think your argument makes it enter the discussion.

"...and assume (generously) herd immunity effects at 70% that halt the progression..."

That's not generous, or not generous, it's just a ballpark guess based on the best (conflicting) data we have so far. You're also discounting the fact that with every individual to gain immunity, the transmission rate is reduced. You're also extrapolating from what may be the worst possible phase of this virus. As time passes we develop better treatments and medications, we have more necessary equipment where it needs to be, we have better early detection and so on.

"...you're looking at mortality rate that swamps that of all wars, terrorist attacks, and natural disaster"

Lots of things swamp those numbers. For example, the flu.

At peak flu season, is seasonal flu the leading cause of death week over week, month over month, ahead of heart disease and cancer?

I haven't looked it up, but 55,000 flu/pneumonia deaths a year is about 153 a day, compared to COVID-19 running near 2,000 a day:

https://public.flourish.studio/visualisation/1727839/

This visualization is from before the acknowledgement that COVID-19 deaths were only counting confirmed positive / presumed positives from the earlier set of CDC symptoms, not the 3x larger set of symptoms revised last week.

Also doesn't account for second order deaths such as those with other health problems not seeking treatment from an overloaded system, or providers in the system committing suicide from PTSD.

55k/yr is also much higher than the actual average number of flu fatalities per year, which is closer to 35k even if you include the preliminary stats from the last 2 years (which captures the particularly bad flu year we had in the '17-18 season).

On the other hand, you can't discount the fact that 20-60K Americans die of the flu each year after we developed a vaccine due to its propensity to mutate. The vaccine is only 10-60% effective depending on the year, while early signs are pointing to COVID not mutating in the same way so a single vaccine (or single infection) may be enough to protect you -- potentially for a very long time.

Taking into account the lack of all immunity to and lack of vaccine for COVID to date, and just how much more virulent COVID is (therefore front loading the disease burden) in the full course of time the flu is almost certainly going to take a much, much larger toll.

It's killed 600,000 people per year, each and every year you've been alive worldwide. So far, COVID is at 1/3 of a year's worth of flu deaths -- let alone a lifetimes -- and are approaching 25%+ of the population of some high profile cities infected. Once it gets to 70% or so, it's most likely going to burn itself out due to herd immunity.

Why are you moving the goalposts? We're discussing US mortality figures, and in the US we have good stats on this, and they average out to ~36k fatalities annually.

I'm not moving any goalposts, goalposts remain in tact. And I'm using the same source: both numbers come from the CDC. So for your reading pleasure:

"It's killed 20-60K people per year, each and every year you've been alive in the US. So far, COVID is at about a year's worth of a bad flu deaths in the US -- let alone a lifetimes -- and are approaching 25%+ of the population of some high profile cities infected. Once it gets to 70% or so, it's most likely going to burn itself out due to herd immunity."

That the flu is a reasonable baseline was obvious enough that I included it in the comment you responded to. The comparison is not reassuring. And the notion that "every individual that gains immunity reduces transmission rate" is exactly what "herd immunity" captures.

Herd immunity occurs when enough members of a population are immune to make sustained transmission impossible. But the transmission rate declines with every immune member of a population, far before herd immunity occurs. Same logic, but a different phenomenon, and one most people seem to overlook.

You're trying to bring galactic brain thought to a rather mundane, simple, calculation. (Fine, 1993) Please don't try to be a contrarian when out of your field, you end up making 'not even wrong' statements

It brought me great delight to watch you confidently declare _you_ are the one with a full nuanced and fair grasp of this situation.

You calculate herd immunity % from R0, and it's odd to decide 70% is not generous and ballpark guess because you think the data "conflicts" - there's no "conflicting" between values in a range, go ahead and cherry-pick the lowest R0 you've seen and find out what the herd immunity % required is based on that (higher than 70%)

Won't even touch you trying to pretend this is the same as the flu, plenty of other threads address that.

I've made it clear already, but just to reiterate, this is one of the worst comments I've seen on HN in a while.

That's more than "somewhat" more lethal.

Er, yes.

Project those C19 stats out across the whole population, and assume (generously) herd immunity effects at 70% that halt the progression, and you're looking at (a) mortality rate that swamps that of all wars, terrorist attacks, and natural disasters faced by the US for the last 50 years, right?

Yes. "Flattening the curve" just means keeping the hospitalization rate below what the medical system can handle. The curve stays flat near the peak rate. See the curves at [1]. The Financial Times has been updating those daily since early March. Some countries show a decline, but other than China and South Korea, which did heavy testing and lockdown, most countries peak and decline a bit, then level out above 50% of peak.

That continues until "herd immunity", either via vaccine or exhaustion of uninfected people. That's somewhere around 70-80% for this.

The vaccine situation is looking up. At least two vaccines are already beginning clinical testing for effectiveness. One from Oxford, one from Germany.

[1] https://www.ft.com/coronavirus-latest

This has been Derek Lowe's shining moment; his vaccine coverage has been fantastic:

https://blogs.sciencemag.org/pipeline/archives/2020/04/23/a-...

It includes additional promising candidates.

As I understand it, and I'd be happy for expert correction: lockdown has additional benefits beyond curve flattening; it also accounts for decreased transmission, which can get us to a point where we can track and suppress outbreaks individually while opening up the economy. That's essentially what seems to have happened in South Korea.

The lockdowns appear to have also stopped transmission of most other infectious diseases. Notably, influenza.

Influenza has a lower R0 than SARS2, and it absolutely kills people. Worth destroying our economy over, all by itself? Ehhhh... I mean, we could have done this at any time, and we didn't, so no.

Nice side effect that translates directly to lives saved? Absolutely.

Does it offset other probable side effects, such as increased heart attack mortality from patients being unwilling to go to the hospital, or increased suicide risk from sudden business failures and unemployment?

No idea, like, none. Biostatisticians are going to be crunching 2020 for the rest of the decade.

The decision is not in reality between "destroying the economy" and "opening the economy up", because even in places that aren't doing strict lockdown, economies are cratering. Even if you opened everything up, people would still make their own decisions to participate or not in the economy, and right now, it looks like they're going to make the economically painful choice.

So then: if you're going to take on a massive economic hit just from altered consumer behavior, does it make sense to get the worst of both possible worlds by also relaxing regulatory constraints that are demonstrably saving lives?

You're drawing more out of that turn of phrase than I intended. Which makes sense under the circumstances, people are drawing lines in the sand and "open at all costs" is one of those lines.

It's not my stance. This is more narrowly-focused than that: we could end the flu season early, every year, by imposing lockdown from January 1st to February 15th.

But we don't, and this isn't the flu, it's a novel disease which kills many more people by even the most conservative estimate.

Still, as a side effect of the eminently rational (and economically painful) precautions which we've taken against it, ending the flu season a couple months early is a nice bonus.

One factor people often forget in the fatality equation is the attack rate, or how many people can be potentially be infected. For the flu, it is around 10% to 15% yearly. For C19, it could be >80% given that there is no natural immunity nor vaccines. Taken that into account, C19 could be at least 40x deadlier than the flul (Flu: 0.1% CFR 10% AR, C19: 1% CFR 40% AR). The 0.1% CFR for the flu is taken from the estimates of the 1957 and 1968 pandemics, which left 100K fatalities in the US. Estimates for the seasonal flu are lower than 0.1%.

Correction: the virus isn't some sort of strange monster in this particular aspect. Have you seen the reports of blood-clotting problems? Sudden deaths from people who'd shown no symptoms? There's still a lot that's weird about this disease and we have a long way to go before we understand it.

I've seen suggestions that a lot of these strange problems happen sporadically with other viruses like the flu too, and it's just more newsworthy when it happens with Covid-19.

This.

All the weirdness and horrors of "normal" diseases are now in the spotlight due to media attention on covid-19.

I'd hold off banking too heavily on anecdotal data. That's how everyone got all worked up about this reinfection story a few weeks ago.

With respect, the story of both governmental and private sector response to COVID has almost universally been not being worked up enough.

Surely the right response to that isn't to always be more worked up.

I think he means plan for the worst, hope for the best.

From what I can tell, the governor in my state (CA) took an appropriate level of actions at roughly the right time (after realizing that the federal government declined to be useful). We appear to be passing through the first big wave of deaths, and cautiously reopening slowly. It's unclear what additional actions would have changed things (in terms of reducing total # of deaths, or any suffering while sick).

Sure, but by getting yourself worked up you're not improving that situation any.

Have we looked closely for blood clotting problems and other odd symptoms with other respiratory system viruses? People get unexplained blood clots all the time. How do we know they weren't caused by a hidden viral infection?

I have a feeling that in 2120 people are going to look back at us as idiots for missing a lot of stuff that will seem obvious in retrospect.

Pretty sure they will have pictures of Florida beaches and the reopen protests beside pictures of the SF Spanish Flu reopening and think we didn’t learn a thing in 100 years.

A lot of the reports you're citing are just press-release-science being turned into breathless headlines.

Those problems are common with regular flu.

I had lots of complications the last year with a common flu. My joints and some internal organs became inflamed because of the immune response and I could not move and was very painful.

This year I got covid early from meeting a person coming from Shanghai. I thought it was a weak flu.

Now I give positive in antibodies test.

> In other words, when you recover from covid-19, you are immune to it. In other words, covid-19 is just like every other virus, in this respect.

"Every other virus" doesn't behave the same in this regard. The viruses that cause colds, many of which are also coronaviruses, are pretty adept at hitting people throughout their life.

Hopefully it's not an issue here, but it's completely unsurprising that people would want to actually research it instead of just declaring all viruses are the same.

The only fools here are the people whose impatience leads them to declare absolutes ahead of times instead of taking preventive measures while the research plays out.

https://www.npr.org/sections/goatsandsoda/2020/03/20/8190384...

> Researchers do know that reinfection is an issue with the four seasonal coronaviruses that cause about 10 to 30% of common colds.

Yes. It's suspected that immunity is very short lived.

> This study provides evidence that re-infections with the same endemic coronavirus are not atypical in a time window shorter than 1 year and that the genetic basis of innate immune response maybe a greater determinant of infection severity than immune memory acquired after a previous infection.

http://www.columbia.edu/%7Ejls106/galanti_shaman_ms_supp.pdf

Even if you recover, there's not a lot of evidence now as to what the duration of immunity will be. With this spreading through the world at different paces, it means that, as commonly predicted, we will see continuous re-emergence as we do with other cold viruses and influenza.

Recovered patients from SARS-1 had long-term antibodies in good concentrations until about 3 years after the infection. We can expect about the same since both coronaviruses are so similar.

Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/

Maybe we will end up putting this new vaccine research to good use and see if we can knock out some of the other coronaviruses. I'd love a combo vaccine that immunized against a bunch of common cold variants.

"it's completely unsurprising that people would want to actually research it instead of just declaring all viruses are the same. The only fools here are the people whose impatience leads them to declare absolutes ahead of times instead of taking preventive measures while the research plays out."

This hypothesis ("SARS-Cov19 does not confer immunity") falls roughly under the same category as intelligent design: the claim is so exceptional that it's a priori unlikely to be found true, and laypeople are taking normal scientist hedge-speak and exaggerating the meaning in their heads (e.g. "evolution is just a theory").

There was never really any question to anyone with any serious scientific training that humans would develop some degree of immunity to this virus. That's why people were saying it was more likely to be assay error from the start. The only open question here is how long that immunity might last. Even then, it's fairly clear that short-term (~months to a year) immunity is highly likely.

(Note: I have a doctorate in biochemistry with a specialty in molecular biology, and I've studied virology and immunology. I'm not just tossing off uninformed opinions.)

> this falls roughly under the same category as intelligent design debate: the claim is so exceptional that it's a priori unlikely to be found true

No. As the person you're responding to pointed out: "The viruses that cause colds, many of which are also coronaviruses, are pretty adept at hitting people throughout their life."

Immunity != long-term immunity.

You can get temporary immunity that lasts for a year or so and still be able to get reinfected multiple times in your life.

And there are hundreds of strains and types of viruses that cause colds. Immunity to a rhinovirus serotype will not help with other serotypes of rhinovirus, let alone all the coronavirus strains and influenza viruses.

"No. As the person you're responding to pointed out: "The viruses that cause colds, many of which are also coronaviruses, are pretty adept at hitting people throughout their life.""

Yes. I'm talking about the question of immunity, not whether or not it's possible to get re-infected by new strains of the same virus, or whether or not immunity fades over time. It would be unlikely that this virus didn't confer at least short-term immunity to the host.

The viruses that cause colds primarily re-infect because they mutate at a very high rate. We aren't seeing that with this particular virus.

One of the currently popular mutants of the virus has a mutation in the proof-reading exonuclease that causes the virus to mutate much more often than the original strain.

https://translational-medicine.biomedcentral.com/articles/10...

"that causes the virus to mutate much more often than the original strain."

This is not claimed anywhere in the paper you linked to. They show a non-synonymous mutation in RNA-dependent RNA polymerase, and hypothesized that it could impact drug resistance.

My bad, I was misremembering the paper, which mentions the exonuclease's role in fidelity. I meant RdRps. The conclusion was the same. Figure 4 shows quite clearly that the RdRp mutation is associated with further mutations.

> We found that viral strains with RdRp mutation have a median of 3 point mutations [range: 2–5], whereas viral strains with no RdRp mutation have a median of 1 mutation [range: 0–3] (p value < 0.001, Mann–Whitney test). The different distribution between the two groups relative to the number of mutations is statistically significant (Fig. 4).

Hmmm, I think I am going to list to the other guy, who has a doctorate in viruses.

> This hypothesis ("SARS-Cov19 does not confer immunity") falls roughly under the same category as intelligent design: the claim is so exceptional that it's a priori unlikely to be found true, and laypeople are taking normal scientist hedge-speak and exaggerating the meaning in their heads (e.g. "evolution is just a theory").

So call the null hypothesis "there will be some level of immunity." But then you see some people testing positive again, and it's reasonable to want to know why. I didn't see people officials leaping to planning for zombie apocalypse "we're all gonna get it over and over forever" scenarios, I saw people saying we needed to dig deeper.

A lot of people in this discussion are refuting a straw man idea that everyone had decided "clearly you get no immunity at all".

> But then you see some people testing positive again, and it's reasonable to want to know why.

I have been following the statements of experts ever since this myth made headlines.

And despite what the headlines said, the opinions of experts has always been clear. That being that these "reinfections" were the result of dead virus material being detected.

So, no it is not reasonable to have ever believed this, if you had listened to the experts.

> The viruses that cause colds, many of which are also coronaviruses, are pretty adept at hitting people throughout their life.

Yes, but you're almost always immune for at least a year. By then, we should be getting close to a vaccine.

And when you do get one of those viruses again, it's significantly less severe the second time.

Governments are reacting to a seemingly very high infection rate with a (best case from the numbers I've seen) fatality rate 10x higher than the flu and the inadequacy of healthcare systems to shoulder the burden all at once (which has more side effects, including more death).

Reinfection can occur with most viruses when a person is exposed too soon after the primary immune response. It takes a while for someone to develop full immunity after recovery. This happened with H1N1 for patients back in 2008.

https://www.virology.ws/2009/12/28/reinfection-with-2009-inf...

Are we talking 2 weeks, a month or 3 months, 6 months+?

Does viral load also matter? I would imagine that getting hit with a high number of viruses shortly after recovery could cause some issues but I'm just an observer in all of this.

In other words, when you recover from covid-19, you are immune to it

How does this follow?

That doesn't strictly follow.

Here is the thought process, though. Typically when you get an infection, your body builds antibodies that can attack the pathogen. The next time the pathogen shows up, your body kills it before you get sick. This immunity doesn't always last for a lifetime, but there is pretty much always some immunity. With COVID-19, early reports showed that this wasn't happening; people got sick, recovered, and then got COVID-19 again. What the news article says is that the test was wrong; when they tested positive the second time, the test was just returning incorrect results (because of limitations of the PCR technique; it's testing for certain RNA, not for the existence of an infectious live virus).

So to say that this means you can be immune to SARS-CoV-2 is not strictly correct. What it says is that there is no reason to think that this virus is any different from many of the other viruses that we already know about. (We do know about viruses that you can't be immune to, like HIV. But those viruses explicitly attack the immune system machinery that is supposed to kill them. We have no evidence that SARS-CoV-2 does that.)

We also know that immunity to coronaviruses generally declines rapidly. We have no idea how long somebody is immune to Covid-19 when they have recovered.

I think it's an overstatement. When you recover from it, you don't still have it, even if you test positive. That means that at least some of the "got it a second time" reports are false.

Are they all false? Don't know. There's hope, but not yet evidence, so far as I know.

> Are they all false? Don't know. There's hope, but not yet evidence, so far as I know.

You mean there's evidence but not proof.

What evidence are you using to show people have recovered who are still testing positive? What confirms that the positive test is false?

Can you provide some sources?

Is this a joke? Literally the article at the top.

No, not a joke, you seemed to be talking from a general perspective rather than "in the results in this particular PCR test in South Korea". As if you had generally applicable information.

My understanding was there were many different tests being used ... so on what basis are you making that generalised statement.

> When you recover from it, you don't still have it, even if you test positive. //

A plausible explanation for specific tests doesn't make this a universal truth; so presumably you are relying on more information? Also, there being an explanation for positive tests based on dead virus, doesn't mean all post-infection positive tests are due to dead virus; that's a massive assumption.

He is right, people may be testing positive just because of dead virus fragments, but to say they have fully recovered there must be no virus alive in their bodies - lack of symptoms may suggest it, then having antibodies may guarantee that eventually..

.. assuming the virus can not hide (and be able to leave) where they can't penetrate - like in the eye ?

.. and with weak immune system the outcome may be (how?)long undecided as the antibodies are not being able to fight the virus fast enough to finish it definitely?

That's how immunity against pathogens usually works. There are exceptions like the flu which mutates into sufficiently distinct strains that the immune system doesn't (fully) recognize. I'm still oversimplifying here.

Well viruses in general, AFAIK, mutate - and that's how we trace their movement through the infected: you sample the virus and look at the mutations eg https://nextstrain.org/ncov.

Do we know for sure that Covid19 in N.Europe isn't sufficiently mutated over that in Australia, say, that secondary infection is possible (even if recovered people's antibodies recognise it somewhat)?

We don't know much for sure.

What I've heard from experts in the field, but I don't have sources, is that the type of RNA virus is different from influenza and doesn't mutate as quickly - which is potentially good news for those hoping for a vaccine.

How would you recover at all if your body weren't producing antibodies capable of killing it?

It doesn't strictly follow, you're right. But this punches a huge hole in the already kind of surprising/unlikely possibility that we had suddenly just discovered the first (or if I'm wrong, "a very rare") virus that can re-infect the same person with the same strain.

In at least two ways I can think of. First, these fragments have been inactivated, probably by the immune system, suggesting you have some immunity (obviously, that's not the same as being perfectly immune). Second, given how infectious the virus is, the fact they're not finding genuine positive re-tests strongly suggests some immunity is happening.

>in other words, when you recover from covid-19, you are immune

Well, it may appear to be the case so far but afaik that hasn't been rigorously confirmed, and this article doesn't imply immunity to live virus upon reexposure.

>but that doesn't mean the virus is some sort of strange monster

Except there are dozens of papers being publishes about a range of effects - damage to a multitude of organs, virus fragments found in brains during autopsy, high incidence of clotting/stroke. By many SME accounts it is very much a strange monster. Also recall the documented rapid progression from asymptomatic to dead.

>It's extremely infectious, and somewhat more lethal than influenza

So one of these numbers (CFR) is about the same, but the R0 is anywhere from 2-4 times larger, and the critical rate appears to much higher than the typical flu. So the response of "terror" isn't totally unwarranted.

>When I first heard about those patients who had recovered from the virus, and yet were still testing positive, it felt like a mistake. I'm glad it's been cleared up.

Agreed. And another reinfection case occured in an immunocompromised patient. So it's looking like the infection doesn't become chronic or dormant.

Note that the immunity is not permanent. The average immunity to the endemic coronaviruses that cause the common cold lasts about a year.

Could you provide a source? Happen to be studying this topic for a paper I'm writing

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

> In other words, when you recover from covid-19, you are immune to it. In other words, covid-19 is just like every other virus, in this respect.

That’s not how HSV works. That’s not how hepatitis works.

You don’t get re-infected by HSV or chronic hepatitis; you don’t recover in the first place. In the first case the virus hides from the immune system, in the second it never properly overcomes the infection.

“Just like other coronaviruses”

There you go

Even that's not true. 15-30% of the viruses that are attributed to the common cold are coronaviruses, and it's pretty clear that the common cold does not behave in the way OP described.

Do you know about genetic drift/shift/different strains?

Moreover, recent literature continues to confirm that you have protective immunity after recovering from covid like any other coronavirus. This is the basis for convalescent plasma therapy

Yes, but you’re drifting from the original point I was arguing against: “all viruses act exactly like the flu, therefore governments overreacted by not immediately assuming it was exactly like the flu” - which has a false premise.

No, it’s you who’s drifting away from “Just like other coronaviruses”

Virtually all messaging I've seen has been "We lack evidence to say how immunity works" with a dose of "there's some initial evidence suggesting immunity" and "we aren't sure about how long it lasts".

It's interesting to read "it's extremely infectious" and "more lethal than influenza" followed by "that's all", not to mention the missing bit about not having a vaccine!

If we saw a massive outbreak of influenza things would be extremely different. We have treatments for influenza (tamiflu), we have vaccines, we have understanding, and a large portion of the population that is already immune.

The similarities are... they are both viruses. Not sure why anyone would compare the two except to try to explain how different they are.

Sigh. I was waiting for the "Govts have overreacted" message. This is a ridiculous criticism to have to the response to this pandemic. We NEED to overreact so we don't underreact.

>In other words, when you recover from covid-19, you are immune to it.

Probably not.

It seems [1] that in humans and animals, there's no long-term immunity arising from infection.

[1] https://www.quantamagazine.org/what-can-other-coronaviruses-...

There have also been cases where people looked like they've recovered, tested negative, and then became ill again after 2 weeks and tested positive again.

I always suspected those were mostly due to false negatives from PCR tests. Probably only a tiny minority of people had not enough immune response for them to become reinfected.

Given a large enough sample size, you're also going to get people who recover, test negative due to a false negative, then get influenza two weeks later, then test positive due to dead SARS-COV-2 RNA.

And various other edge case permutations like that.

I don't think we have any reliable evidence of post-recovery immunity at all. I wouldn't expect to have any until we've seen multiple cycles of this virus, and analyzed the data carefully. Press-release-science during an emergency is close to worthless.

If you don't have any post-recovery immunity, then how do you ever recover to begin with?

immunity prevents you from being infected, not from eliminating the virus. People who are cured of AIDS by eliminating HIV aren't then immune.

HIV is a bit of a special case to begin with, since it's attacking the very immune system that would try to kill it. But is anyone clearing the virus on their own? I thought it required extensive retroviral therapy, and even then it isn't actually cleared?

Admittedly, I don't really keep up on the status of HIV, maybe something has changed.

A very small number of people have natural immunity. https://en.wikipedia.org/wiki/Innate_resistance_to_HIV

I am not sure if anybody gets infected, then clears the virus on their own.

> somewhat more lethal than influenza

My understanding is that most evidence points to order of magnitude more lethal even when the hospitals aren't overflown.

Regarding "testing negative then positive" the experts already expected that there were no real reinfections.

> My understanding is that most evidence points to order of magnitude more lethal even when the hospitals aren't overflown.

If those mortality estimates were based on the number of positive test cases, then they're very likely overblown. Recent seralogical studies indicate that the number of positive test results are likely a small fraction of the total number of cases, and likely the most severe subset at that. None of this is to say that it's less lethal than influenza, only that the situation is developing rapidly and any given mortality estimate may well be outdated.

Well UK deaths from flu are about were 500 deaths per 66M for the most recent year of published cause of death statistics, which I understand (from a couple of papers on annual infection rates) represents about 500/13M infections.

Covid19 figures in the UK are 26,000 [hospital] deaths for 165,000 confirmed infections. Even if we assume the entire population is infected ... that makes it a minimum of 10x as deadly as flu. We're at a slowly falling ~5000 deaths per day; when care-home and other Covid deaths get added ...

I think perhaps you're down-playing it a little too much.

To reiterate the third/last sentence of my post, I'm explicitly not down-playing anything--I'm not asserting anything about covid WRT the flu, only cautioning against drawing conclusions based on potentially outdated information.

In any case, we can all agree that regardless of the value of the number, its "way too many fatalities". My family has lost several colleagues/classmates already. This did not happen in other years. This year is very different, and concerning.

I'm terribly sorry for your losses. It's an awful disease, and loss of life is terrible. It is indeed concerning, but if we can understand whether these fatalities are due to high morbidity or "simply" because it is highly contagious, we can make better decisions about treating the disease, setting policy, etc which can all drive down the amount of suffering and death. That's perhaps a small consolation to those who have lost friends and family already. :'(

> Recent seralogical studies indicate that the number of positive test results are likely a small fraction of the total number of cases

No: the antibody tests were done with the expectation that the total number of the infected would be much higher. The tests have such false positive rates that with the results actually observed the tests in most of the cases say nothing -- in most of the locations the numbers would be similar even if nobody would be a real positive. And there where the results are above these "noise" thresholds we also have a big numbers of deaths which do confirm my claim of order of magnitude deadlier than flu.

Even observing the pure death statistics we can see that, even in spite of all the measures actively taken throughout the world. Without them it's obvious it would have been again the difference of some orders of magnitude:

https://www.euromomo.eu/graphs-and-maps/