FWIW, totally aside from that, CDC numbers for the "flu" are actually a combined "flu and pneumonia", and according to the NHS in the UK-- which doesn't bin the same way-- no more than 1/3rds of those deaths are due to the flu. Other estimates have put the flu well under 10% of flu+pneumonia, though with substantial year to year variation: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3827586/

Even if you steadfastly refuse to accept the obvious exponential dynamics of contagion in a naive population, perhaps the fact that the figures you are reasoning from are off by a constant factor of 3 to >10 might cause you to reconsider your level of confidence?

This. It seems most people are incapable of making decisions purely based on what their mind or the math says. I kind of get it, it didn't "feel real" in the beginning, it was just the mind that went "omg we need to act NOW", not the stomach. I suspect this is why the Silicon Valley Crowd was so far ahead of the curve - they deal with exponential growth more often, and are used to listen to just their brains, for better or worse.

Plus, a lot of the interventions don't really make much sense if you're the only one doing them.

For example, imagine I'm not worried about my own safety, but I am for the safety of others. Staying home and self-isolating will help with this if almost everyone else does it - but if I start a month early, doing it on my own? Negligible benefit.

And of course, much easier to get to work from home at an otherwise-non-WFH company once your boss and their boss are thinking the same way as you, and they've heard Google and Apple are doing the same...

Every day, there's an article describing the new cases or deaths as a "surge". Look for that word: Surge. This word implies that the growth is somehow sudden or unexpected, whereas every day's actual day-to-day growth was predicted pretty accurately months ago. But, if you read the news, every day is described as some surprising "surge". I wish the media would stop calling every day's number a "surge" and start reporting "New coronavirus cases grew at (or above or below) the expected rate, doubling every N days."

Non-math/cs people typically haven't been directly exposed to exponential growth. Which, to be fair, can be an intuitively hard concept until someone sits down and thinks it through. The classic lily pad example is my usual go-to way of explaining exponential growth to someone.

I also think a large part of this problem is societies overall rejection of science, but that's a different discussion.

Actually that's why most public communication for staying at home doesn't say "protect yourself", but rather emphasis on protecting "others" (aka : people vulnerable). The virus is extremely dangerous, but only for a (not that small) minority of people. That's a weird one.

I think one of the biggest public health communication disasters of covid19 is the reliance on mortality as the communication endpoint.

It's acceptable for other threats-- like automotive accidents-- to speak in terms of mortality because there isn't a huge population which is much less exposed to dying but still exposed to serious illness. Automotive accidents also seriously injure many more people than they kill, but not in a way that lends itself to a false impression of immunity.

"Death" makes a nice clear warning for the risks of driving, and other very bad but not death outcomes are just some factor of the death outcomes... it isn't like the audience is comparing death rates to population numbers then deciding that the death from driving isn't worth worrying about just because we didn't also include maimed-for-life.

For covid19 we've ended up making many 20 and 30 year olds believe that it doesn't threaten them. It does. They may not be dying in especially large numbers-- especially where either hospitals are not overloaded or where they're engaging in the ethically dubious practice of triaging younger people ahead of others based purely on their age rather than, e.g. response to treatment--, but they are still becoming seriously and painfully ill and ending up with severe immune system damage -- which takes a long time will recover and will result in latent mortality --, and for many likely lifelong injury in the form of extensive lung scaring.

Infections like influenza are much less contagious-- with an R0 of 1.3 vs 2 to 3 (an enormous difference)--, less deadly, face a population which is at least somewhat resistant (in part due to heroic vaccination efforts) and which knows how to rapidly create new and effective vaccines against it. It's not really that comparable.

I myself haven't yet seen any data that would make this virus any worse than the flu (which means it's still dangerous, just maybe not "everybody-hide-under-the-rock" dangerous). Even data from Italy doesn't show mortality any higher than previous years.

Do you have links to data that supports what you wrote?

I agree it is a communication disaster though. If I see another chart with red line, logarithmic scale, not starting from zero or with some approximated (red) curve that doesn't specify the formula... :-/

Doesn't that require a study after the fact? So your proposal is to just wait and see?

BTW, how do you explain the unprecedented hospitalization and ICU rates in Northern Italy?

As an example, this report from European Society of Anaesthesiology[1] mentions:

> The number of intensive care beds in Italy continues to change. Initially, there were 500 public intensive care (ICU) beds in Lombardy, and 140 private ICU beds. However, now there are more than 900.

[1]: https://www.esahq.org/esa-news/analysis-of-covid-19-data-on-...

A lot of people aren't tested unless they are severely sick, they're just told to stay at home.

When they arrive in the hospital they're already in a pretty bad condition, and only then tested. Which means that no therapeutic actions are made until patients are admitted, with the exception of self-administration of paracetamol.

> The number of intensive care beds in Italy continues to change. Initially, there were 500 public intensive care (ICU) beds in Lombardy, and 140 private ICU beds. However, now there are more than 900.

But a lot of ICU beds were slashed in the past 10 years due to budget cuts, and we were at 80% capacity when the virus hit. If the testing keeps on like this, and we can't even palliatively treat patients until they start suffering respiratory problems, these problems will continue.

What do you think the mechanism is here? Why are people being hospitalised with covid-19, if it's not covid-19 causing the hospitalisation?

People under 50 don't spend much time in ITUs on ventilators, until covid-19 happens and now the ITUs are full of people with covid-19 having air pumped into their lungs to push the fluid out.

What's causing that if not covid-19?

People are counted in the stats produced by hospitals if they have the virus, not if they've been hospitalised because of the virus. Literally if someone breaks their arm and they're tested positive, that goes into the stats for "COVID-19 cases". This is also true if someone dies of anything whilst having the virus; they're recorded as a "COVID-19 death".

The statistics here don't tell us what they sound like they're telling us. We'd see exactly the same pattern if the rules were suddenly changed to require every hospital admission to be tested for the common cold in a regular year - the number of "cases" and "deaths" would increase dramatically every day.

People under 50 don't spend much time in ITUs on ventilators

That statement is far too vague. People of all ages spend time on ventilators every years, especially during a flu outbreak. This is especially true of young children (under 5) whom COVID-19 doesn't affect at all! And COVID-19 is known to affect very few under 50s; the numbers here are so tiny the media can literally write entire stories about individual cases.

So what does "people" and "much time" mean in this sentence?

You can see some data on deaths from pneumonia by age group here:

https://ourworldindata.org/pneumonia#pneumonia-mortality-rat...

Of course deaths isn't the same thing as hospitalisation as the young are more likely to recover than the old. So this data isn't exactly what you're talking about, but it's at least quantifiable.

It's not safe to make a claim about this virus without comparing it to known values from prior years or outbreaks, when comparing the same thing. Every single number we're being presented with is presented without context and it leads to catastrophic mistakes of understanding. Number of positive test increases is shown without the number of negative test increases as well (i.e. an exponential increase in testing looks like an exponential increase in cases), deaths are counted without any investigation to decide what caused that death and so on.

It's very easy to get a totally misleading impression of what's going on. This is likely why in so many parts of the world hospitals are now reporting themselves as empty for weeks, despite the supposed "exponential growth" that should have overwhelmed them by now. In fact in Switzerland hospitals are needing to apply for emergency funding because the huge drop in patient numbers has caused their revenue to dry up.

There's clearly a virus spreading. It sends some people to hospital. Quite a few viruses do that.

Unlike those, this virus is different in one key way - governments have decreed that any death where the virus is present is counted as a "virus death", and have decreed mass testing to find infections. Consider a virus that is not really dangerous but highly infectious, like any common cold or flu. Then many people will turn up at hospital with it, but in reality their problem is something else. With our current data that would look like hospitals being flooded in a way never seen before, but it'd be a data artifact, not something real.

As for countries having to build makeshift hospitals, two things:

1. Local overloads happen during bad flu seasons too. You can find many reports in the past about wards being converted, tents being constructed to hold patients on the streets from earlier flu pandemics. Arguably making quick hospitals to handle that sort of bad flu season should be a more common practice.

2. No country anywhere is experiencing general overload. Even in Italy, a few days ago a politician was publicly asking why they're sending patients to Germany when in nearby Veneto there are hospitals that are 2/3rds empty.

Projections of mass death requiring everyone to shelter-in-place are based on the belief that everywhere will "go Bergamo" simultaneously at once. That isn't happening, it's not even close to happening.

Go investigate and you can find stories of deserted hospitals all over the world right now. They've been cleared out in anticipation of an imminent surge that isn't appearing. That's why Germany and Switzerland can take in patients from neighbouring countries - not only are there no makeshift hospitals but hospitals need financial bailouts because they've having to pay so many staff who are basically idled, like many other businesses.

Clearly there's a huge mismatch between the global view and a small number of local hotspots, and our understanding of what's happening is heavily coloured by the press.

If we succeed at slowing the growth, even stopping it, then thank god those hospitals will remain empty.

e.g. here's German data:

https://swprs.files.wordpress.com/2020/03/infizierte-pro-tes...

and US data:

https://twitter.com/FScholkmann/status/1246122535793680386

It looks like it doubles every few days because of the rapid increase in testing.

Moreover these hospitals are now entering their second week of being idled. They should be very busy by now if the sick were really growing exponentially - they're still mostly empty.

Even in New York you see this:

https://www.dailymail.co.uk/news/article-8173563/Elmhurst-ta...

"New York City's Elmhurst hospital - the 'epicenter of the epicenter' - is now receiving fewer patients but they are arriving sicker, doctor warns, as he says some come in with no symptoms other than diarrhea then test positive"

"He said testing was surprising and that some people show up with a fever and cough but test negative. Others who are there for different ailments - like car accident victims - end up testing positive."

New York is supposed to be the epicentre of the outbreak yet the most overloaded hospital is now seeing fewer patients arrive than before. That's not consistent with being at the start of a very long exponential growth phase (it obviously can't grow exponentially forever so this discussion is only about how long it lasts in that phase and where the peak is).

Edit: got throttled, will reply to Joe here

Many sources show only the number of positive cases and deaths. Here's one that shows total tests performed in the USA:

https://covidtracking.com/data/us-daily

On the 5th April 2020 there were 332,308 positive cases in the USA. So the halving point was between 29th and 30th March (139,061 and 160,530 cases respectively). It took about 5 days to double.

On the 5th April 2020 there were 1.42 million negative cases. On 29th March 2020 there were 692,290 negatives or 48% of the figure today. It took exactly the same amount of time to double.

So we can see that number of tests doubled in that time. Total tests went from 831,351 (47%) to 1,762,032.

The proportion of positive to negative cases is 18% today. On the 29th March it was 16%. A 2% rise, nothing even close to doubling. The graph in the tweet I linked to shows this visually - a fairly smooth and slow increase over time. We think it's spreading exponentially because of misuse of data, but all that's actually growing exponentially is testing. And yes - that's probably why there are now global shortages of reagents and other ingredients for tests. You can't keep globally doubling demand for tests without eventually hitting production limits!

Look at the worldwide data, then at the data for pretty much every country: https://gisanddata.maps.arcgis.com/apps/opsdashboard/index.h...

Its geometric growth pretty much any place you look. Now, unless testing were proceeding completely uniformly across the board, its hard to imagine that explains any of this.

This is an example of how you are making straw man arguments. No-one is arguing that the growth rate will continue to be exponential in the face of effective mitigation.

We're not testing the general population. Its testing of folks coming to a hospital? Folks who aren't having hospitalizing symptoms are not tested at all, and sent home to quarantine.

So if tests doubled that means that folks are feeling bad at an increased rate. Showing up at a hospital with alarming symptoms.

You can finagle the statistics both ways - by ignoring what the 'test sample' is and assuming its uniform for instance.

You're right that it's not a uniform sample, but the consistency across the world is very suggestive. Not everywhere has test shortages.

It links to a document from the Intensive Care National Audit and Research Centre.

The evidence from actual covid treatment doesn't support the "they die with, not of, covid" argument.

That's just like Covid though - they are counting everyone who dies with the virus even though most have other conditions.

This is the latest data published by the Italian Ministry of Health. Looking at the chart on the second page, try to ignore the lines (we all know there is an infinite amount of ways one can approximate a curve to the dots) and just observe the dots. Does this seem like a bad year to you? Compared to winter 2016/17?

http://www.salute.gov.it/portale/caldo/SISMG_sintesi_ULTIMO....

Also note that all the charts are misleading since they don't start with 0 (the effect is exaggerated).

https://www.ecodibergamo.it/stories/bergamo-citta/coronaviru...

Doesn't that seem like a bad year to you?

Overall mortality for Europe is lower than during most flu seasons:

https://www.euromomo.eu/

Week 13 is march 22-28 if I counted right. Deaths lag cases. French Coronavirus deaths went from 674 on the 22nd, to 2314 on the 28th, to 8078 yesterday april 5th.

I would say your comment is premature.

The thing you are missing though is that crisis started mid March. It feels like forever (because of shelter at home), but it is a very short time and every few days the number of cases doubles. Most of that doesn't register on graphs that spans multiple years (look at the dates).

Every cold and flu grow exponentially.

Not sure what the fixation of HN readers is on the work exponential. Although true, using it doesn't add anything to analysis of corona virus specifically.

I'd rather talk about the false hope in ventilators, and the futility and destruction to our economy by lockdown.

The issue of exponential growth is of relevance in response to those saying that the number of deaths (insert the inplicit 'so far' here) is much less than from infuenza (annually.) It is not a 'fixation' to expose the irrelevance of that line of thinking.

More generally, the issue is a combination of the facts that this virus is significantly more dangerous, for all age groups, than at least post- Spanish Flu infuenza; it is very readily transmitted; and there is no (or much less) herd immunity. When you combine these fact with the math of exponential growth, and have establshed the doubling rate, you can do some scientific prediction that goes beyond "so far it has not been as bad as the flu", which is true just so long as it is, and no longer. To do that, however, you have to hold more than one idea at a time in your head.

It seems there are a ton of people right now who are enjoying thinking of themselves as intellectually and even morally superior to people who are just pointing out facts about the statistics gathered so far (which point to flu-like levels of danger and properties). I think the HN community is especially prone to this because it's full of computer programmers who are used to thinking in powers of two; some seem tempted to ascribe near-magical wisdom to this familiarity. But nature isn't a computer and just saying "exponential growth" over and over will eventually make fools of a lot of people, because it isn't there.

If this virus was really spreading exponentially, you'd expect to see the proportion of positive tests going up exponentially as well. But that isn't what is seen. In places that report the total number of tests administered (some places don't), the proportion of positive tests increases sub-exponentially or even hardly at all, coming to rest at about 15%, which is roughly the background level of coronavirus infections in the population during normal times.

It's especially disappointing to see PG fall into the trap of blaming politicians. Politicians have in the blink of an eye ceded power to a tiny cabal of (primarily) epidemiologists. So far they by and large aren't asking questions, instead simply doing whatever they're told even if it makes little sense.

But we really need people to start asking those scientists difficult questions. Citizens can do it but ultimately it only matters when politicians do it. Epidemiologists have a track record of absolute failure. They failed with Zika, they failed with foot and mouth disease, they're failing with CV. Go look at the models they produce and weep; some are invalidated the day they're published!

This guy is doing a good job of pointing out the many errors of modellers:

https://twitter.com/AlexBerenson

There's also some background here:

https://blog.plan99.net/is-epidemiology-useful-a4ec54e59569

What we are supposing is instead that the number of people who are presently infected will increase exponentially IF we don't adopt measures to decrease the spread. This is actually what you saw in the initial period and what you would be seeing now if we did nothing extraordinary to decrease the spread. If you look at the 1918 flu epidemic it ultimately infected 1/3 of the population. It is utterly unclear to me why you imagine your understanding is better than that of the experts. It would seem you yourself are guilty of the same sin you ascribe to programmers? From your animus towards the profession are you perhaps a manager of same? If so you seem to have contracted at least one of their faults.

> politicians have in the blink of an eye ceded power to a tiny cabal of (primarily) epidemiologists.

This literally isn't real.

The politicians are indeed at fault for the poor response. We cede to them substantial funds and powers to both prepare for and response to situations just like this. In fact the pentagon prepared a report on literally just this exact crisis in 2017 that called out among other things a lack of supplies. We opted to do nothing of import between now and today. In the crucial early days of this crisis instead of instituting effective measures we were busy first ignoring reports of it and then publicly claiming it is a hoax. If we aren't brave and clear sighted enough to even ascribe blame how are we to do better next time?

Even the highest positive rates I've seen (in the UK where the testing situation is dire) are only 30%. In other countries with more tests it's around 15% and stable over long periods.

If the number of infected were truly growing that fast, then you'd see the proportion of positive tests go up and up until negative tests were hardly happening, but that isn't close to what's seen on the ground.

What we are supposing is instead that the number of people who are presently infected will increase exponentially IF we don't adopt measures to decrease the spread

That's not what policymakers are supposing. If that were true there wouldn't be a global run on ventilators, which assumes enormous growth over case load today.

This literally isn't real.

That's not much of a response. Where are there politicians not saying their decisions are just guided by the science? The only places where politicians even pushed back slightly on epidemiologists are Brazil and - briefly - the USA.

At this time what epidemiologists say should be done, is done, no questions asked. In Denmark they are even restricting speech to stop people criticising the adopted measures, or so it's said. Look at what happened to my post above - even investigating or criticising those currently making the decisions is suddenly penalised.

A tiny number of academics with no track record of accuracy have obtained enormous power now. If they say lock down, countries lock down. If they say close the borders, the borders are closed. If they say open up, countries open up.

It's right and proper that such people be subject to the same scrutiny as normal politicians are.

As for politicians having done nothing, I don't think that's fair. Does the USA not have large stockpiles of ventilators and masks? Perhaps unusable in the end, but that level of detail is not for politicians, only civil servants. As for beds, well, even assuming the modellers are right no healthcare system in the world can have tens of thousands of ICU beds empty, sitting for a once in a century pandemic. Politicians who tried to have such levels of slack would soon be replaced by others who cared more about utilisation. I don't think there's much to say about them at this time; for better or worse they've taken a back seat.

If people are doing well, the economy will likely catch up-- weak businesses will fail, new ones will be created. It may hurt, may hurt for a while-- but from a purely economic perspective this might turn out to be a useful reboot. There are going to be a lot of phenomenal opportunities in the coming year.

But the economy cannot do well if the people are not.

For a thought experiment, imagine for a moment that we didn't need to keep delivering food and power and whatnot. It would be possible to simply pause the entire economy-- just like contracts that don't consider weekends business days-- in this fictional world we could freeze all accounts and all debts and whatnot for a year and then do "2020" over again. We can't do this because we need to keep a lot of people working to keep food and medical care flowing-- but I think the crazy idea is a useful illumination that the economy is a shared delusion. Whats going on now is only as devastating as we allow it to be, but the deaths of millions would be devastating (economically and otherwise) regardless of what we otherwise want.

No, that's true only if it's brand new. Immunity for a certain strain lasts several years, which means there's a level of herd immunity that constraints infection from even reaching some of the non-immune folks, hence it's hard for it to be exponential.

This is not the case with the 'novel' coronavirus. There is no large scale immunity among the population.

When it is growing exponentially, they close a few schools here and there or stop visits in hospitals. That is enough to stop spread, get the R below 1 and making it not exponential.

It is simply not true that every cold and flu grows exponentially.

For many layperson, this is their first experience when it really matters. My mom isn't sitting around thinking about exponential spread when she gets a cold.

> I'd rather talk about the false hope in ventilators

I agree. Something like 80% of the people who end up on a ventilator die. Of course those other 20% are happy one was available, but by the time ventilators are being discussed it's really too late. Prevention is key.

> futility and destruction to our economy by lockdown

Depends. The economy was going to be hit hard regardless. Even if nothing was ever forced closed, the number of people sick and the number of overwhelmed hospitals would have killed the economy. For example, even before there were any official lockdowns in the US, companies I work with were already stopping all travel (late February timeframe).

In the US, the flu kills between 12,000 and 61,000 people each year depending on the season. COVID-19 will almost certainly reach the low end of that range in between two and three days. It went from 100 to more than 9,000 deaths in only three weeks.

It's not the flu.

P.S. everyone who can get a flu shot should, every year, regardless of age. Herd immunity assists in protecting the entire population.

January 2017 was much worse overall in Europe, it's not even comparable.

Still, if you focus on Italy, which is the most ahead in Europe, by March 28th (the time that report was updated), the number of deaths was already matching the 2017 peak (and in about 2/3 of the time). Since then the death count went up 70%.

edit: also note the caution about the uncertainty due to delayed registration.

The data is still lagging by a few days, but it seems that the numbers are starting to trend down.

It looks like flu, among other reasons, because popular comparison at the time compared all-ages mortality for flu (e.g. including old and sick) with healthy-young-person mortality of the covid. This very same comparison also ignores asymptomatic covid people and does not ignore asymptomatic people with flu. So it is twisted in all kind of ways.

1. People are often contagious well before showing symptoms, making it much harder to track and isolate the people who have it.

2. It is about 10x more deadly than the flu. Could be more than that, as it's difficult to extrapolate from the current messy data. But I think it's safe to say it is much more deadly than the seasonal flu.

So far more people getting it, in a very short period of time, and a much higher percentage dying or requiring hospitalization, giving us the results we see. Overwhelmed health care systems, and death counts that will be much higher than seasonal flu without large scale mitigations in place.

Comparing a number that is static from year to year to one that is growing exponentially is mistake number 2.

CDC data shows 220k known-tested-positive case and 22k associated death. The 36 millions case is pulled out of a hat. As per these number, seasonal flu kills 10% of the known-positive cases.

Medical professionals aren't professionals in everything. You may have been asking the equivalent a frontend developer for advice on writing COBOL for z/OS.

We are collectively guilty of many errors in judgement but on the whole we show on average not only are we able to mostly behave competently in complex situations individually we are able collectively to make some systemic changes to decrease mortality over the years.

This gives me hope that we take the correct lesson from this terrible experience and adjust our individual and collective behavior to avoid a re occurrence.

The main difference was it took the superior part of the throat instead of the inferior. Talking with doctors they tell me I had all the symptoms.

The problem with it is that at first it is "benign"(I had high fever for "just" two days) if your body stops it before getting into the lungs. Once it gets there it could be nasty(as it produces cytokine storm syndrome there) very fast.

So it is very easy to get confident.

Even the flu could get very dangerous is you get it combined with something else like a bacteria at the same time.

incredibly simplified accessible articles on mainstream health websites, stating that a symptom is "throat pain"

or having to go through 20 pages of medical research which I understand basically nothing of.

Have you stopped saying that, or are you still saying it for some reason?

>It made me realize how getting vaccinated for the flu as soon as you reach 50 may actually be a pretty good idea..

Do you realize, you can, and probably should, get vaccinated for the flu each year? And that these vaccines are only a 'best guess' for that particular year, so you should get on each year?

>It actually made me realize how the whole world has been completely desensitized to catastrophic predictions.

I suppose the alternative is to not warn people about pandemics and just let them all run wild? I'm sorry if people choose to get "desensitized", but these organizations are not interested in the politics of whether or not the general public will be able to appropriately digest their messages, and hence don't ration warnings based on how much we can "handle".

I'm not so confident yet. What is still worrying me, is that it is not clear about the importance of the initial dose with respect to the severity of the outcome.

The disease having a quite slow progression, may mean that if you let it spread wildly, suddenly there is a large percentage of the population exposed, and this mean that when people gets contaminated they receive a high inoculum which may bring down even healthy individuals.

And the total death toll, given the current dynamics, is already going way way worse than the flu.

2018: Flu stomps the nation, overwhelming ERs and leaving 20 children dead: https://www.cnn.com/2018/01/12/health/flu-surveillance-cdc/i...

2013: Flu Outbreak Overwhelms Hospitals: https://fox8.com/news/flu-outbreak-overwhelms-area-hospitals...

2017: Hospitals Overwhelmed by Flu Patients Are Treating Them in Tents: https://time.com/5107984/hospitals-handling-burden-flu-patie...

I still have yet to hear from the medical and nursing schools about increasing the number of students for the future.

The flu is still terrible, btw. And I hope this situation will increase the vaccination rates for the flu

I just wanted to explain my initial reaction, based on what happened in china and by reading various medical people give their opinion.

Fully aware of the types that will come out of the woodwork for simply saying this, however: no, it's currently still not on track for even a mild flu year yet alone a bad one.

A bad year for influenza is about 650,000 deaths worldwide, pneumonia deaths are often an aftereffect of the flu and it kills 2.5 million on average each year.

SARS-COV-2 has killed 60,000 in 5 months despite having no vaccine or known medicinal treatment, mainly due to locally overstretched medical resources more than anything else.

It's not even close to being equivalent to a bad flu year yet, and that's ignoring the secondary deaths.

Maybe about tenth your figure, once you exclude non-flu pneumonia-- which is about where we are now for covid19. Flu death figures are Flu+Pneumonia because they usually don't check. Efforts to separate flu from flu + pneumonia all result in flu being a small fraction of the total ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3827586/ ).