[DiogenesKynikos]

The ratio of asymptomatic to symptomatic people has been measured, and it's not nearly as high as you're saying. China has been quarantining and testing every single person entering the country, and they find that 2/3rds of cases are asymptomatic.

Moreover, Germany has conducted a randomized serological survey of the population of one town where there was a large outbreak, and determined that the true mortality rate was about 0.4%, which is an order of magnitude higher than mortality due to the flu. That's the mortality if there's excellent healthcare and the system isn't overwhelmed. Mortality will also depend on the age structure of the population, rates of obesity and smoking, etc.

Because a large fraction of the population is immune to the seasonal flu (both through vaccination and previous infection), far fewer people contract it than would contract CoVID-19 in an uncontrolled epidemic.

The combination of a much larger rate of infection than the flu and far higher mortality means that CoVID-19 would kill orders of magnitude more people in one year.

[arcticbull]

> Moreover, Germany has conducted a randomized serological survey of the population of one town where there was a large outbreak...

1. Results showed 0.37% mortality rate, which is an order of magnitude lower than the fatality rates being published, which is what I claimed -- so I re-iterate: "The numbers we're seeing are an upper-bound, by an order of magnitude." [1]

2. 14% of their town has had it already. [1]

3. That 0.37% rate includes all the old and at-risk folks which I was already suggesting we isolate. Since we know the fatality rate for them is 9% in hospital vs 0.1%, I'd suggest that the actual mortality rate of my plan would be incredibly low. [1] We don't know the demographic distribution of the town, and we do know that the disease is incredibly age-dependent so it's hard to project that onto the population.

Either way the flu is 0.1% so this isn't 10X worse, it's 3.7X worse. At most.

4. The study shows 15% of them are already immune to COVID.

[edit] I found the data [2]. Out of a population of 12,000, 6500 of them are in a risk group (over 45). So 55% of town. This needs to be projected onto the world population factoring into account non-linear risk response.

> Because a large fraction of the population is immune to the seasonal flu (both through vaccination and previous infection), far fewer people contract it than would contract CoVID-19 in an uncontrolled epidemic.

I don't think they are. The flu mutates regularly, and there's a ton of strains. Vaccinations are only 19-60% effective depending on the year. This is evidenced by the 650,000 worldwide deaths (60,000 US) and the 45,000,000 US cases of the flu each year.

[1] https://www.technologyreview.com/2020/04/09/999015/blood-tes...

[2] https://www.citypopulation.de/en/germany/nordrheinwestfalen/...

[DiogenesKynikos]

> The flu mutates regularly, and there's a ton of strains.

... which a substantial fraction of the population is immune to. Only 5-20% of the population gets the flu each year. CoVID-19 will infect 60-70% of the population, at a minimum, unless measures are taken to contain its spread.

> Results showed 0.37% mortality rate, which is an order of magnitude lower than the fatality rates being published

I've seen most people assuming a mortality around 1%, which is not that far off from these results. In Italy, 1% may well be correct, given how the healthcare system was overwhelmed there.

> I'd suggest that the actual mortality rate of my plan would be incredibly low.

If you can successfully shield the entire at-risk population, which easily approaches half the population of many countries. Once you add up old people, obese people, people with diabetes, smokers, people with heart conditions, and all the other at-risk groups, you come to a sizeable fraction of the total population. Trying to shield those people while the virus infects most of the rest of the population sounds incredibly risky to me. It's not even obvious that you can achieve natural herd immunity without at-risk people getting sick, because you need 60-70% of the population to get sick.

Overall, I don't understand the motivation behind such a risky plan. Why not just go through a 6-week period of lockdown, and then control the epidemic afterwards with extensive testing, good contact tracing and social distancing measures? Countries other than the US appear to be successfully implementing this strategy. Some, such as South Korea, were acted competently enough that they didn't even require the lockdown phase.

[arcticbull]

> Only 5-20% of the population gets the flu each year.

Only 20% of America is 70,000,000 people. That's staggering. The economic impact of the flu is enormous.

> I've seen most people assuming a mortality around 1%, which is not that far off from these results. In Italy, 1% may well be correct, given how the healthcare system was overwhelmed there.

It may be 1% in Italy because the population of Lombardy was overwhelmingly old, and overwhelmingly sick. The average age of death in Italy was 80.5 and the average number of underlying medical conditions was three.

[amadvance]

> may be 1% in Italy because the population of Lombardy was overwhelmingly old

Multiple official sources in Italy estimate that the real number of infected is 10 times the reported one. This explains the high dead rate.

[DiogenesKynikos]

> Only 20% of America is 70,000,000 people. That's staggering.

So imagine 4x as many people getting infected with a virus that is many times as lethal.

> It may be 1% in Italy because the population of Lombardy was overwhelmingly old, and overwhelmingly sick.

And the US has other problems, such as obesity. But the mortality will be much higher wherever the virus overwhelms healthcare systems. As we've seen, that can happen very quickly.

[arcticbull]

If we, again, assume that 15% of the US has already had it (as in Gangelt), and that herd immunity kicks in at 60-70%, that means we'd expect to see another 45-55% of the population -- 147-179 million cases. If we actually isolate the vulnerable, basically nobody would die.

[DiogenesKynikos]

That would be an incorrect assumption. The Gangelt study is about one small town in Germany where there was a known superspreading event at the Carnival festival.

If 15% of the US had already been infected, then based on the Gangelt study, there would be 200 thousand deaths, and millions hospitalized with severe illness.

You're completely misreading the Gangelt study.