The only way to know would have been to perform tests, which we did not do.
All the antibody studies so far suggested infection numbers that were massively higher than confirmed cases.
Furthermore the PCR tests used for initial diagnosis have high false negative rates and most people with only mild or no symptoms never got tested in the first place.
They're still higher than usual, and so any 'even at the peak' appeal to curves acknowledges that epidemiologists were probably correct and numbers of cases rose very rapidly from near-negligible levels, before slowing due to social distancing measures. If the disease was widespread much earlier, excess hospitalisations and deaths during that period ought to be much higher than they are now with aggressive social distancing having been place for nearly two months. It's not like France has limited access to healthcare or was more likely to chalk a surge of hospital inpatients with severe respiratory symptoms off as something else in late Feb or early March than in late April, when despite lockdown they were much higher...
Viral pneumonia is among the most common cases of death among the elderly.
Influenza cases vary significantly between years.
There is a lag of infection to death of two to three weeks.
It would have been invisible for a long time, spreading uncontrolled.
BTW, that 50% is for national level and with a shutdown in place.
Regions hardly hit by the virus have a much higher excess mortality (Bergamo province 450%, NYC 390%, Madrid 250%, Manaus 250%) [1]
[1] https://twitter.com/jburnmurdoch/status/1256312094334619648
It simply would not have registered among the usual deaths from viral pneumonia, which has a year over year variance of a similar magnitude.
The actual death numbers are also highly dependent on the age groups affected, in Germany for instance there is no discernible excess mortality because most of the infected are below the age of 65.
Disease spread tends to always show a pretty standard shape. It was that observation (Farr's law) that led to epidemiology being born as a field. It grows, it peaks, it enters immediate decline. Importantly the peak doesn't last long - epidemics don't spend 6 months with a stable number of people getting sick at the peak. Look at graphs of COVID deaths and cases and you'll see the standard pattern.
We know now that this virus has left hospitals virtually everywhere without overload, even in places like Sweden. A few other places were hit much harder. But the response in New York (with mobile morgues) wasn't reported anywhere else. It's apparently some kind of invention of New York policymakers during a brief peak rather than a worldwide phenomenon.
A virus can be spreading and growing for a long time before it attracts attention. The evidence keeps mounting that the first reports in Wuhan were not in fact the first cases after COVID had mutated or crossed from animals but merely the first where doctors decided to search for a novel virus after coming under pressure and noticing some novel symptoms. What you saw in New York was a mix of:
1. Conditions at the absolute peak of infection, not at the start.
2. Media hype and fake news.
For (2) I present https://nypost.com/2020/04/01/cbs-admits-to-using-footage-fr... as evidence. CNBC spliced video from an ICU in Italy into reports about New York without telling anyone. Outright deliberate deception is also the tip of an iceberg: there's far more selective reporting, exaggerated anecdotes and so on. On April 6th Vox reported the entire USA was running out of sedatives needed for ventilation:
https://www.vox.com/2020/4/6/21209589/coronavirus-medicine-v...
On the same day Gov Cuomo was saying they had enough ventilators with some in reserve. A few days later he was sending them to other parts of the USA.
Whatever you think you know about the situation in New York you really only have a tiny fragment of the whole picture (and the same for me and everyone else posting here). Our understand of reality lies shattered in pieces on the floor, smashed by speed, poor quality data, poor use of data, and extremely poor journalism. All we can do is work to piece together a narrative of what really happened by examining all the evidence we can get. Repeated anecdotes from many different people about having had a COVID-like illness before it was being discussed much are interesting for that reason.
So I am capable of personally falsifying your statement:
>But the response in New York (with mobile morgues) wasn't reported anywhere else.
I lack a citation but I'm not really trying to prove anything either. I don't think New York is isolated. Lombardy seems to be stricken pretty hard, and it's hard for us to know what it was truly like in Wuhan.
Also nursing care homes make up a significant part of the deaths: some infected patients from elsewhere were put there under the "promise" of keeping them separate from the others, and you can imagine what happened later.
What's interesting is that many US states have shown virtually linear growth for more than a month, which is an extended "peak", assuming it's a peak. That depends on if enough of the population is exposed before the interventions are relaxed, or else it will just revert to its natural progression and the media will have something exciting to report on again.
The US data is tricky to interpret because the nation's testing rate has been growing relatively slowly. Over the past week (Covid tracking project data), the US has reported about 242k tests/day; for the week ending April 7 (so 4 weeks ago), that number was 144k tests/day.
In the meantime, an extended peak is consistent with the idea that policy measures in place have reduced the R0, but only to a value close to 1. Suppose stay-at-home orders reduce the number of daily contacts by about 70%, taking the R0 from 2.5 to about 0.8. With an infection period of two weeks, that would only reduce the number of new infections per day by 35% after a month.
The UK, France, Spain, and Italy are all countries that have temporary morgues because of covid-19.
> On April 6th Vox reported the entire USA was running out of sedatives needed for ventilation:
They link to this document. Are you saying this document is incorrect? How do you know it's wrong?
https://www.ashp.org/Drug-Shortages/Current-Shortages/Drug-S...
Aside due to the fact that there were high number of cases and the skewed death rate towards the elderly, couldn't also this be due to the fact that (at least in Italy) tests are done only if a patient is hospitalized?
I mean, the evidence is so far scant and anecdotal, but the timeline for treatment (I'm aware only remedisivir has been proven to be effective, but protocols also use other drugs, even if the efficacy is unknown) suggests that the earlier the treatment, the more effective it will be.
If only admitted patients are tested, that usually means a lag from symptom onset, which may ultimately be detrimental.
Only without intervention. With social change, the disease's R0 (with respect to a given society) will differ, altering the shape of the epidemic curve.
We can have great confidence that COVID has not gone through a full, "status quo" epidemic curve anywhere.
Take Italy as an example. That nation has conducted (as of May 2, Wikipedia data) 2.11 million tests to find 210k positive cases. That 10% test positivity rate forms a loose upper bound on the prevalence of nCoV in the entire population -- even if we assume that policymakers erred and many infections are asymptomatic, test-selection criteria should not have caused a worse than average chance of detecting a positive case.
In the meantime, Italy documented 28,710 COVID-related deaths as of that date. If we again make the generous assumption that all COVID-related deaths were detected but the true population prevalence was about 10%, that would give the disease an 0.48% IFR. That's far too high for a rapidly-spreading disease to remain hidden for long.
Simultaneously, we can't say that the supposed 10% infection rate is sufficient for herd immunity. If 10% of the population is infected now when the virus was introduced at the end of December, the R0 of the disease must be well above 2 (with a generously short two-week period between infection and recovery -- shorter than many observations -- we've only had 8 generations.) Herd immunity would then require > 50% immunity in the population.
Instead, the much simpler conclusion is that policy responses have worked, with lockdowns and distancing reducing Italy's R number to somewhere around 0.75 (based on a rough look at the number of new cases per day, divided by the number from two weeks ago).
> All we can do is work to piece together a narrative of what really happened by examining all the evidence we can get.
Yes, but we must examine all that evidence in light of what we know of epidemiology. It's far too easy to cherry-pick data that is comforting or aligns with our political predispositions.
> Repeated anecdotes from many different people about having had a COVID-like illness before it was being discussed much are interesting for that reason.
... but the plural of anecdote is not data. Especially for a disease such as COVID, where the range of attributed symptoms is so wide that just about any commonly-circulating cold or flu could -- by symptoms alone -- be attributed to nCoV.
Italy will slowly get out of lock down soon (while still preventing travel across regions). We will see how it goes.
