Keep in mind, the UK advisors think the peak is maybe two months away, and that at-risk groups may need to self-isolate for a month either side of that peak. This is a far bigger response than any country has achieved so far (and it's extra difficult because the at-risk groups are probably the most dependent on external aid, as well as already lacking social contact). I don't think they're wrong to think that this will be difficult to achieve, and increasing the difficulty by starting earlier will make things worse.
There is no SCRAM button on this pandemic, not any more at least.
How have they achieved this? What concrete measures?
Assumption 1: Our country will not be able to take measures that are extreme enough to stop exponential growth. Assumption 2: Once a certain level is reached, we can drastically lower the doubling time so that the number of simultanious cases are kept below what our healthcare system can handle. Assumption 3: If we stay below the level that the healthcare system can handle, mortality rates will be low, maybe lower than 1%. Assumption 4: The total number of individuals that will require hospitalization is low enough that the healthcare system can treat all patients needing treatment in a few months.
If assumptions 2 is not met, the mortality rates of pations that require treatment is likely to be similar to what is seen in Italy, ie roughly 15%.
If assumption 3 is wrong, and the real mortality rate is about 3-5%, having about half the population infected, will still lead to huge numbers of dead, more than the population is likely to accept.
If assumption 4 is wrong. Italy is currently unable to handle 20000 cases. A country like the UK may be able to handle maybe 10000-20000 simultaneusly. If 10% of the population requires hospitalization, and each patient will stay there an average of 1 month, measures will have to be dragged out over several years, anyway.
Assumption 5: This only needs to be done once, meaning there will not be second or third waves or mutaded viruses that will need to spread in a similar fashion in the same time period.
At some point, I think every country will realize that they need to take drastic measures, enough to stop the spread from being exponential. Doing that after detecting 100000 cases is VERY different from doing it after detecting 1000.
The downside, of course, of preventing exponential growth, is that most measures will have to be kept in place until there is a vaccine or other cure, and that could take 2 years.
From my perspective, it appears that politicians do NOT want to take sufficiently drastic measures, as the economic consequences will be huge (let's assume that Spain and Italy will keep or increase the measures they already have for 2 years), and so far, their measures do not seem to be sufficient.
That's why I dont understand the crisis communication on the subject. I understand exponential growth, I dont under and the panic about getting sick with a flu like virus.
If it was something causing skin lesions I'd be in panic mode because the victims would be at a higher risk of co-infectious diseases. This is not that. But hey, fuck my civil liberties some more, for that matter fuck my freedom and that of my countrymen. I dont give a fuck anymore.
The flu and the common cold virus behave comparably to the current pandemic. The flu in particular kills about 300K per year after infecting about 20% of the global population. That's a mortality rate of 0.02% and a survival rate of 99.98% for the general population, which is not a fun statistic, but nothing to panic about either.
Critically, the hospitalisation rates for the flu are so low that the current infrastructure can handle it. People still die, but only if they couldn't be saved with medical intervention. Much of the time they will receive treatment and live.
Even if you shift the numbers around a lot -- say, 50% infection rate -- the orders of magnitude come out to about the same. Governments can just put out ad campaigns to encourage people to get the flu vaccine to compensate for a particularly bad flu season.
The critical thing with the cold and the flu is that they move well past the initial exponential growth phase into a "logistic curve" long before the hospital systems become overloaded with the sick. That is, each new strain of the flu runs out of victims by hitting the population ceiling of 7.6 billion. Not everyone is vulnerable, and the rest either become immune or protected by herd immunity.
Now compare this to the Coronavirus. It has a mortality rate of about 0.8% of confirmed cases, with medical care. Much more importantly, about 10% of the confirmed cases required intensive care.
Nobody really knows the ratio of confirmed-to-real cases, but I'll be generous and assume that only 20% of all cases get a confirmed diagnosis, with 80% of cases just shrugging it off as a case of the "sniffles". Similarly, I'll assume that the virus will halt at around 20% of the total population.
For Italy, with a population of 60M people, that's 12 million infected, equivalent to 2.4 million confirmed cases, 240K in intensive care, and 19K dead.
But I lied.
I lied when I said "240K in intensive care". There just aren't that many beds, or intubation kits, or CPAP machines, or even oxygen masks. There aren't anywhere near enough doctors, or nurses, or any resource you care to name. I know this to be true because all of these things have run out already.
Long before the exponential curve starts to "slow down" and become logistic, the entire medical infrastructure becomes overwhelmed and the cases that "would survive with intensive care" turn into "deaths".
Worse, this happened at a "confirmed case count" of about 10K. I said 2.4M above!
The conclusion is that the Coronavirus can overwhelm medical systems waaaaaaay before it hits the "knee of the logistic curve", making it a nearly pure exponential curve. Exacerbating this is the incubation time, meaning that any measure taken today will have essentially no effect for at least a week.
Act now and save lives, act tomorrow and see your loved ones die.
This is the difference.
3blue1brown explains it quite well, and I recommend everyone watch his video: https://www.youtube.com/watch?v=Kas0tIxDvrg
But if someone throws on just enough additional Uranium for the pile to go supercritical, you would run for your life because none of the following will matter[1] all that much to the final outcome:
1) How much neutron radiation there was to start with.
2) The specific exponential growth coefficient.
3) How much total Uranium there is, as long as it's a nontrivial amount
4) Whether your Geiger counter is off by some constant factor or not.
None of those matter. It's going boom. It might go boom a bit sooner or a bit later, but it is going to go boom. That's just how exponential growth works. There's no maybe. There's no "let us wait and see". There's no "we'll hope for the best". No: It. Will. Go. Boom.
All of the factors that are irrelevant are just shifting a figurative vertical wall on your graph paper a bit to the left, or a bit to the right. It's adding or subtracting "a couple of doubling times". If the doubling time is short, then you're not really achieving anything by fiddling with constant factors.
With the Coronavirus just about every country has a doubling time of 4-5 days.
I live in Australia, where we're about a "month behind" everyone else. So of course, the dumbass government is saying things like "the heat here will slow it down". But it hasn't, our doubling time is 4.75 days at the moment. They're saying that it's "premature to lock down the country". No it isn't, it's already weeks too late and getting literally exponentially worse daily! They're saying that the hospitals are being prepared, but no amount of extra beds or ventilators will help. If they double the number, it just delays the catastrophe by 4.75 days. Not even a whole week! Quadrupling beds and ventilators buys just under 10 days before people are being turned away to go home and die.
So, again. I ask you: If you were the nuclear physicist in charge of a nuclear pile and someone told you it's gone critical and the radiation is rising exponentially, is your first reaction to: just "stand around and wait and see what happens", or to: take drastic action right this second? Do you SCRAM, or do you call the communist party leadership for permission? Are you the hero of the Chernobyl story, or the villain?
[1] Ignoring thermal effects slowing down the reaction. This actually has an analogy with disease spread, where there are fewer susceptible people remaining because everyone is already sick or dead. If we reach this point, we'll be seeing millions infected and hundreds of thousands dead.