Just_a_fan wrote: ↑14 Mar 2020, 13:32
I don't think millions will die at all. I think we'll end up with a similar death rate to "normal" 'flu. That's not great, of course.
Disclosure - I'm not just repeating stuff I read. I worked in the UK healthcare system in various roles for 15 years, and was head of comms for a Primary Care Trust covering a population of nearly half a million during the Swine Flu pandemic. About 70% of my job related to Swine Flu during that period, and quite a bit on other immunisation programmes like measles, mumps and rubella.
'Normal' flu death rate is 0.9%. Real world experience of Covid-19 seems to be between 3% (China) and 8% (Italy). It's going to be at least three times as bad as seasonal flu just in terms of death rate. Because it's a very contagious disease, because immunity is currently 0 and because we have no vaccine, a lot more people will get it than seasonal flu.
Just_a_fan wrote: ↑14 Mar 2020, 13:32
Herd immunity requires fewer than 50% of the population to have been exposed with the pandemic influenza, for example, up to 90+% for things like measles.
It doesn't quite work like that. Herd immunity is not just a function of exposure, it's also a function of how contagious an infection is, and Covid-19 seems to be significantly more contagious than flu (as measles is, which is why we need more than 90% (actually around 95%) for any herd immunity effect to work. In those other infections you mention, it requires a systematic immunisation programme.
With flu we generally have a level of existing immunity and vaccinations developed for new strains within months - the degree of herd immunity we achieve is contingent on the success of the immunisation programme. I've seen the term 'herd immunity' misused a huge amount over the past few days. Yes, we generally achieve a degree of herd immunity with seasonal flu, but anything from 30% to half the population can still be at risk, and that's when it goes well. Spanish flu had a first phase that ripped through the population, and then the exact same strain came back and caused even more deaths. One season's exposure was not enough to confer meaningful herd immunity. With measles we had virtually total herd immunity in the late 2000s, but that has started to fail due to antivaxx campaigns etc.
You do not get herd immunity by exposure alone - or rather, if you do happen to get herd immunity that way, it's because you've killed off all the vulnerable people.
Just_a_fan wrote: ↑14 Mar 2020, 13:32
Assuming COVID-19 is worse than pandemic influenza, we might need 70-80% to give herd immunity. That means that most people, who are healthy enough to get COVID-19 and recover quite happily, need to protect the 20% (the old and those with underlying health issues). To minimise loss of life, we the young/healthy need to take it on the chin, feel rubbish for a week and then move on. We need to do this whilst limiting exposure of those who can't take it so easily. That's why Govts are espousing the self-isolation technique - stay at home, feel rubbish, recover, move on. Don't go to hospitals and other places where old/ill people are gathered together. Don't go visit granny to check if she's OK. Let the medical care system do that. The old and the ill will thank you for it.
Running around shouting "we're all doomed!" isn't going to help one little bit.
Nobody is 'running around' or shouting about being doomed - with the benefit of my experience, I believe that this is significantly more serious than seasonal flu, and significantly more serious than other recent pandemics. Refusing to accept the gravity of the situation will not help anyone either. There is going to be a 'new normal' we have to get used to.