[fyp]

Even with worst-case scenario of bias, this is still extremely good news. My worry was always with super spreaders who refuse to isolate but the data is suggesting that those spreaders will still soon achieve herd immunity among themselves. As long as the rest of the society behaves we will still hit zero cases relatively quickly.

(which wasn't always clear to me before since I initially predicted that this will take years to work out)

[hcknwscommenter]

I don't think you are looking at this right. It will still take about a year (+/- a few months) for this to run through the population of the country. NYC spreads faster and was hit harder and earlier. Still only about 1/5 have had it. The remaining 4/5 (maybe 3/5 if there is some fraction of people that just are naturally immune/resistant) are going to get it. It's going to be a while to get there.

[athrowaway3z]

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.

[newacct583]

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.

[athrowaway3z]

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%

[zaroth]

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%.

[nodamage]

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

[hcknwscommenter]

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.

[bagacrap]

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)

[wbl]

Superspreaders aren't connected to each other.

[analyst74]

> those spreaders will still soon achieve herd immunity among themselves

that's not what herd immunity means, unless we isolate those spreaders so they don't get in touch with "non-spreaders"

[RandallBrown]

The non-spreaders are the people who are self isolating.

I think they're saying that people who go out and spread the disease will quickly catch it, recover, and be unable to catch it and spread it. That relatively small group of people who are refusing to self isolate, will gain herd immunity, causing the virus to die out in that group of people, preventing them from giving it to the non-spreaders that have been at home the whole time.

Whether or not it will work out that way, I don't know.

[djannzjkzxn]

While this dynamic may exist in some form, I don’t think it’s a powerful enough affect to stop the spread. There is not a firm dichotomy of spreaders vs. isolators and the composition probably changes over time, such that the virus still has many opportunities to spread to previously-isolated groups.