Some additional random musings:

1. Mortality data
Maximum attributable mortality continues to decline at 15% overall, and around 1.6% excluding Hubei. Harder to get a gauge outside of China since fewer patients discharged. But around or even less than 1% appears to be the case. I think overall mortality, which will only be figured out in retrospective studies, will be less than 1% of all infected, but it seems it will be higher than 0.1%. Probably around 0.5%, which would put it into severe pandemic influenza territory.

2. Overall mortality/morbidity burden
Mortality rates by themselves only tell a small part of the story, since the total burden will be a function of how many people get infected. Diamond Princess suggests that most people are susceptible. Neil Ferguson at Imperial has suggested 60% of the global population could get infected in a full-blown pandemic. I think that's unlikely because once we've breached 10%, global infrastructure will start to strain considerably and the global economy will take a huge hit....this will in turn kick-in massive behavioural modification (if not, hopefully before it gets to this!) that may mitigate spread. This is what we've seen in non-Hubei China. Transmission 'hot-spots' i.e. cramped quarters such as cinemas etc will just shut down. SARS-CoV2 appears more contagious than influenza from what we've seen. Given that pandemic influenza typically infects 10-20% of the global population, let's go for an estimate of 20%.

With a mortality rate of 1%, that would still mean 14 M deaths world-wide, 600k deaths in the US etc. That is way more than the global healthcare infrastructure can deal with, and may push mortality rates up, but it may also push contagion down due to massive shut-down of the economy. Just writing this makes me really upset.

If we get the beginnings of a pandemic, i.e. clear loss of global containment, but fairly limited spread, massive behavioural modification as suggested in my post above, may limit spread to below 10% of the global population infected, and if COVID-19 is seasonal, it may not even reach 1% of the global population, at least until the Autumn. Even though influenza is seasonal, H1N1 peaked in summer 2009 from memory, so I'm not fully holding my breath. If we get less than 5% of the global population infected, this may prevent health-care infrastructure collapse. To put into context, the total number of confirmed cases in Wuhan currently is <0.5%, and probable actual prevalence is <2-3% and we can see what impact that's had on the city.

I say the above that some conspiracy theory posters have suggested that China has purposefully hidden the true extent of the disease, otherwise why the massive response...I don't think it needs to have "hidden" very much (right now) to explain the situation on the ground. For sure, Wuhan has more than 50k cases I would estimate, but it doesn't need to 500k for things to go really bad. I also don't think we're missing a lot of "serious" cases outside of Hubei in mainland China (except possibly in the countryside)...there's just no incentive internally or globally for that to happen.

3. Other knock-on effects

As an infectious diseases physician and researcher, it has always struck me that saving a life from cancer is worth (e.g. in the US) around a million dollars, but saving a life from infectious diseases is typically worth less than $1k. This is understandable from an individual psychological perspective: if you live in a rich country, you are more likely to die of cancer. But it doesn't make sense from a public health or governmental perspective: folks like me and more clever than me have been saying that infectious diseases pose a greater existential threat to the status quo than any other threat. But it's always been a hypothetical existential threat. The irony of the current COVID-19 outbreak is that a) due to a combination of global response/ luck/ stuff we don't understand, this doesn't become a global pandemic: in which case, people go back to complacency, b) things do turn out badly, in which case, it's a bit late to say "I told you so".

If we are fortunate enough to develop a vaccine against COVID-19, I'm wondering what will happen to the pernicious anti-vax movement that is highly prevalent in developed economies. Again, the anti-vaxxers have always had a point: the chance of a child born into a rich country dieing of polio/measles/whatever has been remote, even with Disneyland-assisted measles outbreaks etc. But COVID-19 brings with it a small, but not discountable risk of major morbidity (?10%) and mortality (?1%). That's huge compared with most infectious diseases the average rich person will encounter.

More generally, will there be a shift in western countries where individualism is paramount to a more eastern mindset where things need to be balanced against the public good. Note, this is not a political stance: even in e.g. Japan, (the total mismanagement of Diamond Princess excepted), the idea of protecting others when you are sick is a typical and normal consideration.

tb