This paper seems to have every imaginable scenario of which 2022 is a worst case.

But, now actual data is starting to come in - such as the extremely interesting serum testing in Scotland (1) - which suggests that the infection rate is much much higher than previously supposed. The Scotland serum testing shows that around 35000 people were infected at a time when only 110 cases were known officially, and strongly suggests that at least 10%-20% of the country have been infected by now.

Similar data has been suggested by the Danish serum testing.

So I'd be interested to see what comes out of this Harvard model if they put in the numbers suggested from serum testing.

1. https://figshare.com/articles/Serological_analysis_of_1000_S... )

And also a similar study in Germany with similar results [1]. The result is of course to mechanically reduce the fatality rate to a number close to that of the flu (the problem for hospitals being not so much the fatality rate than the high number of infections), and well within the 0.1-1% range that US health authorities have been advertising for a while.

Regarding models, it seems 0.15% is the new basis [2].

Even on the optimistic end of the range (0.1% fatality), with 13k deaths, that's 20% of the UK population infected, a long way from achieving herd immunity.

The other thing is that I invite people on hackernews to better control their anxiety. It is not so long ago that pointing that case fatality ratios in jurisdictions that didn't do mass testing and where there seemed to be many unreported cases with mild symptom was overestimating the fatality rate would get you treated of conspirary theorist. South Korea had been measuring a fatality ratio in that range (~0.6%) over a month ago and that was probably already an upper bound (due to not testing 100% of the population).

[1] https://mobile.twitter.com/AmeshAA/status/124944656101010637...

[2] https://mobile.twitter.com/AmeshAA/status/124902067755179622...

NYC population is 8.4 million. Their death rate is 6,589 (Apr 13). 0.1% of 8.4 million is 8400, that would mean almost everyone in NYC has been infected, I'm not sure that is feasible at the moment.

https://www1.nyc.gov/assets/doh/downloads/pdf/imm/covid-19-d...

It would only take a 0.25% fatality rate to imply 30% of the NY population to have been infected, which is plausible.

The people who were treating that hypothesis as an absurd conspiracy theory last month probably won’t own up to it, but I do hope they are reading.

That's not really what those people were saying.

It doesn't matter if the number is 5% with a low infection rate, or 0.5% with a very high infection rate: both will lead to very large numbers of dead people unless we take severe action early on.

And so far they've been right. Covid-19 is causing huge amounts of excess mortality, even when compared to a really bad flu year.

Source? Europe shows excess mortality spiking to a similar level as the 2017-2018 flu season: https://www.euromomo.eu/

And that’s with elective procedures being cancelled and everyone scared to go to the hospital for any reason. Here’s some new data indicating that half of the excess mortality in England might not be caused by COVID-19 itself: https://archive.is/2eKCW

South Korea’s fatality ratio at the time was obviously lagging, and has since gone above 1%. The true infection fatality rate might still be low but certainly the final case fatality rate won’t be, even with their mass testing.

As of April 9, according to Wikipedia, the CFR of covid-19 in South Korea reached 1.95%

The early pointing to South Korea’s CFR as low turned out to be misleading in the end due to I guess some issues relating to the data (probably because many cases were ongoing and the persons had neither died nor recovered).

That's a lot of interpretation from 6 cases. There's a lot of serological testing being done right now, and we'll have hard data soon, but from what I see from expert epidemiologists (disclosure: I'm not one myself), the idea that we have a vast number of completely asymptomatic cases is wishful thinking.

Ah, but if you do a sample of 1000 then even low numbers of positives are still statistically significant. The poisson distribution on just 6 might be somewhat wide but you can give a reasonable confidence interval (ie 0.3-0.9%) - and either end of that interval still suggests a lot of undetected cases at a time when there was hardly any officially.

What you can't do - statistically - is say "oh there were just 6, that means it all could just be a coincidence and the prevlence is actually very low".

Especially when - if you dig into the numbers they make sense. First, they were spread over a 2 week period, with all the positives being in the second cohort - which is what is expected if there's an exponential explosion of cases going on. Secondly, 4 of the 6 positives are in the Edinburgh area which is the most internationally connected and affluent area of Scotland.

So I really don't think it can be breezily dismissed just because you don't like the data. But as you say, we'll have a lot more serological data before long so lets see.

edit: removed for potentially being misleading.

Cross-reactivity is an issue in the ELISA test (the actual antibody test).

But they validated their results with a second step, the "pseudotype neutralisation assay". This test is highly specific for SARS-CoV-2 - as I understand it, they essentially introduce the virus to the hypothetically immune blood samples and then test that it is indeed neutralised by antibodies.

So, I think this Scottish serology test is pretty robust and accounts for these issues with cross-reactivity and specificity of the testing. In addition - they used a control sample from December 2019 none of which tested positive.

0 out of 100 controls and 6 out of 500 gives a very wide confidence interval. You could easily get those numbers with 1% false positives and no true positives in either group. Is your prior for false positives low enough to rule that out?

They did two independent assays so I would think the false positives rate should be far below 1% - certainly the authors seem to think so.

Secondly if they were false positives, I would expect them to be randomly distributed. Not concentrated in the affluent capital city, and not solely in the second cohort with none in the early march cohort (as you would predict if exponential growth is occurring).

Why even test 100 controls if your conclusion relies on a prior that false-positives are much less than 1%? I think that shows the author's are worried about false-positives and have failed to rule them out sufficiently.

Your second two points are fairly compelling.

Yeah, I read more into their assay and I'm inclined to agree with you.

Here's an expert thread (for example): https://twitter.com/richardneher/status/1250533354560159745

The tests might be inaccurate. Current antibody tests seem to conflate the common cold with covid-19, as they are both coronaviruses.

https://edition.cnn.com/2020/04/14/health/coronavirus-antibo...

That is not the case for this study, see here for why:

https://news.ycombinator.com/item?id=22879363

That is good news if that's the case!

There is a study in Germany done on an outbreak in Heinsberg that has a similar result.

When “sero samples” are done like this is there any effort to notify the donors their blood has been tested and come back positive for the antibodies? Ideally donors would be notified either way but at the very least I think the people with positive results ought to be informed.

"To avoid this, prolonged or intermittent social distancing may be necessary into 2022."

Wow -- seems very unlikely to happen though.

Intermittent seems quite possible. Every time the death rate spikes, we'll have to lock down again.

Chances are, some region will decide against doing that, and their outcome will provide a clear incentive for everyone else to be more rigorous about it.

That's happening right now with Sweden and it's sure to be a pretty interesting case study. Their health system hasn't yet been overwhelmed, but they've had a lot of cases (and a lot of deaths), especially on a per capita basis for a smaller country:

https://www.theguardian.com/world/2020/apr/15/sweden-coronav...

Of course, some right-wing media outlets have still been touting this as a success and a model for a less economically-damaging approach— this article is from nine days ago, but it's not hard to find other similar ones:

https://www.nationalreview.com/2020/04/coronavirus-response-...

It's probably much too early to say one way or another, but I guess there is some value in having multiple approaches be tried. Particularly in a world where guys like Glenn Beck have gone on record saying they'd "rather die than kill the country."

Funny world we’ve come to when right-wingers are pointing to Sweden as an example of how they want to handle an issue.

But in Sweden vs Norway, we are talking about 4x the case numbers adjusted for population, and a few hundred dead.

The data might turn much worse, but right now I don't think it's bad for Sweden.

Yeah no this is not happening, the young people will revolt before that. You can suspend civil liberties for a few months, that's fine, but not intermittently over several years. No way that governments in western countries will get away with that. I expect this to be an event that will remove most baby-boomers from power and bring in the millennial generation, they expect us to support ~5 old people through most of our productive life and now they created or are about to create debt that we will have to pay off for the rest of our lives. A lot of it is to prop up pension schemes and assets which are primarily owned by old people and projected to have collapsed by the time a 30 year old will retire.

It seems like around me young people take the virus more seriously then old people.

Lmfao you are far too optimistic about the revolutionary potential of westernized young people.

They will not revolt. They won't take power. They don't even vote today.

I take the "Ok boomer" to be the canary in the coal mine, or atleast I hope so, because without the young people revolting this planet is royaly screwed.

I think you underestimate how things can go from apathetic to extremely violent in a short period of time. There have been lots of violent (and non-violent) mass protests in several countries of Europe, for far smaller reasons, during last few years (https://en.wikipedia.org/wiki/2011_England_riots, France has the yellow west movement https://www.youtube.com/watch?v=L_-W2_X5yS8 (this is happening despite the shutdown), Spain violently shut down Catalan independence last year, Italy is governed by a protest party, Germany had the Pegida and Friday's for Future Protests).

> Chances are, some region will decide against doing that, and their outcome will provide a clear incentive for everyone else to be more rigorous about it.

I used to have a poster along these lines in my office. https://despair.com/products/mistakes

This one might be relevant too: https://despair.com/products/consequence

> Every time the death rate spikes, we'll have to lock down again.

this will likely cause more business failures than a prolonged shut down. Starting up and shutting down a business is not free. There are legal costs and you need to source materials for operations. In the case of restaurants in particular, there will be loss due to spoilage

I'm starting to doubt this.

What about Sweden vs Norway -- sure, the data is 4X worse for Sweden, but we are only talking thousands of infections and hundreds of deaths. Maybe this can't scale to bigger countries though.

This article brings up something I was thinking about when this all first started: cross-immunity with other coronaviruses and whether or not infection with one of them could at least give partial immunity to SARS-CoV-2. As the study points out, there are less harmful human coronaviruses which are thought to cause around 15% of common colds worldwide.

I wonder if anybody has thought to research using these viruses as part of an innoculation strategy at least for high-risk groups. After all the first 'vaccine' ever developed in the 18th century (really an innoculation) was to intentionally give people cowpox in order to give them immunity to smallpox.

Maybe it's too risky though for some reason? I dunno.

The existing human coronaviruses aren't the most well-researched things around, but as I understand it there's evidence infection with them might actually be pretty dangerous to at-risk people. They just can't cause a pandemic because too many people are immune.

The common cold is dangerous to people? The flu, sure, but I never heard of people dying from a cold. I'm sure it happens, but in comparable numbers though? I don't think so.

You may already know this, but for the sake of others, it’s important to realize that many viruses cause what we refer to as ‘common cold’. Coronaviruses are only a minor component of this set of viruses, as low as 1-2% in a study I read (can’t find it now; this value also depends on lots of factors).

FWIW this WebMD article I read a while back puts "colds" as being caused by Coronavirus 20% of the time, https://www.webmd.com/cold-and-flu/cold-guide/common_cold_ca....

This migth depend on location and local climate. The typical cold in my country has different symptoms and length then typical cold 8 hours of drive away south.

I had heard 1/4 of the common cold are Coronaviruses. Thanks for clarifying here though. I tend to be very short on HN for practical purposes.

Too late to edit my comment, but a somewhat authoritative source claims 10-15% of colds are caused by coronaviruses (UpToDate, if you're curious). The study I read may have been referring to a specific coronavirus that was mentioned in the original post.

It happens all the time, in exactly the same sense that people are dying “from” COVID-19 (i.e. usually combined with other morbidities). How much of this pandemic is due to the disease actually being worse than other coronavirus diseases, and how much is simply due to the rapid spread/no pre-existing immunity, remains to be seen.

Who else here remembers learning that AIDS patients (people with acquired immunodeficiency) can die from the common cold, in school? Is it not common knowledge that old folks can die from a cold, too?

Covid-19 is killing healthy young people with no known pre-existing conditions at very high rates. It just happens to be killing the elderly and those with comorbidites (which includes normal ailments like diabetes and obesity) at even higher rates.

It isn’t just some new common cold that we don’t have herd immunity for. Different viruses have different lethality; common cold corona viruses are far milder than SARS-Ncov-2 which is in turn far milder than MERS.

Is it corona virus, or ventilators, killing them?

When you have a mortality rate of 66% to 90% for something tha isn't a hemorrhagic fever, it's the ventilator.

People were dying without ventilators in Wuhan and elsewhere. (E.g. all the people in NYC who are dying at home, something like 100 a day last I saw)

The ventilator from what people are saying doesn’t seem to help as much as was hoped, but it’s not like hospitals are killing the patients by putting them on a vent, which is what your comment seems to imply?

People dying in care and nursing homes are not on ventilators. This may be a significant number of covid-19 deaths.

https://ltccovid.org/2020/04/12/mortality-associated-with-co...

> Key findings:

> Official data on the numbers of people affected by COVID-19 is not available in many countries

> Due to differences in testing availabilities and policies, and to different approaches to recording deaths, international comparisons are difficult

> Data from 3 epidemiological studies in the United States show that as many as half of people with COVID-19 infections in care homes were asymptomatic (or pre-symptomatic) at the time of testing

> Data from 5 European countries suggest that care home residents have so far accounted for between 42% and 57% of all deaths related to COVID-19.

While there is speculation that ventilators might be worsening the situation, it's ridiculous to suggest that 66-90% of people with ARDS might die, with or without a ventilator. There are other ways to die from a viral lung infection than just hemorrhagic fever.

* meant to say "might not", not "might".

I disagree. I'm unable to find any source with numbers. At best I've seen the statement "it's rarely fatal except in very rare circumstances".

Like the flu, you don't die from the flu, but really it's the last straw on top of other issues that pushes people over the edge.

But the flu is far more deadly than the common cold, it's misleading to talk about them together like that.

There are no numbers. Nobody has ever bothered to measure it separately from pneumonia. It’s hardly ever tested for or listed under cause of death, even when it’s obviously a factor. Once things change in the aftermath of all of this, we will see if your instinct is correct.

Well it turns out I'm wrong about this, there are some studies with numbers but they're pretty rare:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3655081/

> Twenty-two percent of all subjects with isolated coronavirus were hospitalized, but in the population aged ≥60 years this increased to 73%. While our study design precludes the determination of exact hospitalization rates as a result of coronavirus infections, the hospitalization rates were similar to those for influenza.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4181476/

> The high proportion of non-influenza infection in this study (72%) underscores the importance of non-influenza viral infection in contributing to severe illness necessitating hospital and ICU admission in adults, as has been found by others.

Certainly not the same mortality rate, but the common cold does kill people every year due to pneumonia, asthma attacks, etc.

Maybe we could give them to people who aren’t at-risk though, so they are more likely to fight off covid -19 and less likely to transmit it around.

Its been thought of, but I think these kinds of things aren't considered acceptable today. I do wonder if there is some variant of Coronavirus that has been in circulation for a while that causes some immunity, though. There are some strange things in the data, IMO, but there are lots of other possible explanations too.

Yeah I’ve been asking about this for a while with no good answers. Why aren’t we looking into whether it would be helpful to enable every healthy person to get the Coronavirus common cold to help boost herd immunity?

Normally modern medicine doesn't make people sick deliberately, because some percentage will always have some time of reaction. And the US is also a litigious society.

However, I'm in favor of ending lockdown and letting corona virus run its course, just like the flu every year. That's the fastest way to get herd immunity.

Yeah, but letting it run its course kills off at least 1% of the population and causes potentially long term lung damage for a sizable portion of the rest of the population.

You might be interested in this discussion about that: https://news.ycombinator.com/item?id=22830320

It's mind blowing we are not putting more money, Billions of dollars, into why people are getting reinfected and around antibodies.

It is fully expected people will be able to get the disease again in years.

But it might be much sooner. And when you get it a second time it might not be as easy as the first. Your third winter and third time getting it might be death.

This variable turns SARS-CoV-2 from it's current media accepted 'mild' to very serious, and we don't know what it is, these 3 months into the disease.

Ok link talking about some of the issues -

https://www.nytimes.com/2020/04/13/opinion/coronavirus-immun...

Actually we don't have to do anything except let corona virus run its course. Just saved you billions in research.

“Run its course” = 2-3% of the population die due to the virus.

I think the billions in research might be a more humane alternative.