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by athrowaway3z 2247 days ago
What?

All of these numbers are inline with what experts have been saying and modeling for more than a month. We will be dealing with this for at least another year. We will cycle through policy to loosen up and close back down a little. In the best case for NYC they are 1/4th of the way to herd immunity in numbers. With the drop in transmissions, this might be 1/8th of the way in terms of time. There will be more deaths in the future than have been recorded so far.

Look for the bright side in things, but zero cases is a pipe dream.
2 comments
newacct583 2247 days ago
Herd immunity doesn't mean 100% exposure. It means a high enough incidence of antibodies such that the effective R0 goes lower than one, meaning that new outbreaks tend to shrink over time and not grow.

With most endemic viruses, antibody incidence is somewhere around 30-50% I believe, but I haven't seen any modelling for what covid is expected to do specifically.

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athrowaway3z 2246 days ago
If there are a high number of asymptomatic/mild cases that are to infectious to others this means it will have to be more. i've seen numbers between 70% and 80%. Thats why i took 1/4th to mean 80%
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zaroth 2247 days ago
25% prevalence is absolutely not in line with what experts were saying on March 23rd. Nor was an IFR of 0.5%.

The CDC reports that flu has an IFR of ~.13% in the US (61,000 deaths out of 45 million cases). That makes 0.5% roughly 3.3 times worse, not 10.

Also, herd immunity does not require 100% having positive antibodies, it will show an effect on Ro starting around 65%.

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nodamage 2247 days ago
Bear in mind that the CDC estimate of 45 million influenza cases[1] is the number of symptomatic cases, and therefore it doesn't really make sense to directly compare that with Covid-19 IFR rates calculated from antibody studies which include both symptomatic and asymptomatic cases.

[1] https://www.cdc.gov/flu/about/burden/2017-2018.htm

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hcknwscommenter 2247 days ago
It's not 25%. 0.5% versus 0.13% is not the only issue here in terms of how much worse it is. It's the long time in the ICU. The flu kills you fairly quickly or you get better fairly quickly, so you don't take up hospital capacity so long. Herd "immunity" does not require 100%, but that's a decent approximation. Sure, I'll grant that it "starts" to show an effect around 65%, but the effect is not so strong. 70%, much stronger. 80% very strong. Heck, you could probably do containment by then without waiting to get to 100%. Because inadvertent spreading would be so low.
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bagacrap 2247 days ago
it would show an effect on r0 immediately, but around 65 is when r0 would hit 1 (since it's got 2/3 fewer chances to spread and starts at about 3)
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