[tghw]

NYC had only 20% prevalence in mid-June[1], after they had contained the initial outbreak[2]. Therefore, the drop in new cases is very unlikely to be from herd immunity, which would need prevalence to be in the 80% range.

The author seems to ignore that most people are interacting with far fewer people because they are working from home, kids mostly aren't in school, and our other interactions with people outside our household have been limited and altered to decrease the chances of transmission.

It's nice to think that some people had memory T-cells that could deal with the virus, and it seems some people do, but based on the original R0 numbers, it would be foolish to think that is the case for enough of the population to conclude that we've reached herd immunity.

[1] https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/comm...

[2] https://coronavirus.jhu.edu/data/new-cases-50-states/new-yor...

[rdtwo]

The theory was that some large percentage of population is either immune or at least significantly more resistant to covid. Do once the initial 20% get it the other 50-% are resistant so you get your 70% number that way

[tghw]

Barring concrete evidence that is the case, it's a very dangerous assertion to make. It would also mean that the transmissibility of SARS-CoV-2 is much higher than we originally thought, amongst those without "natural immunity".

Even if it were the case that half the population was naturally immune, we would want to understand why. The leading explanation at the moment is T-cells and previous exposure to other coronaviruses. Problem is, there's a good chance that previous exposures would be less likely in certain populations, like children, which could be especially problematic as we're debating sending kids back to school.

At the very least, we need more data on T-cell prevalence/reactance to SARS-CoV-2 before we can jump to the conclusion that people are already immune.

But right now, it's far more likely that we've seen drops because of the drastic measures that have been taken and the changes in daily behavior across the population.

[anoncake]

We already know that the virus is harmless to children. No need to grasp at straws to pretend that our collective hysteria was necessary.

[Tainnor]

While kids are less likely to get sick from it (less likely doesn't mean zero cases or even deaths btw), they can sure as hell spread it. There was some research suggesting that they're spreading the virus as much as (or not detectably less than) adults [1]. Yet at the same time, there are also some indications that kids might be less likely to become infected [2]. How that will affect school reopenings is anyone's guess.

[1]: https://zoonosen.charite.de/fileadmin/user_upload/microsites... [2]: https://www.nature.com/articles/s41591-020-0962-9

[anoncake]

Less likely doesn't mean zero cases, but non-zero doesn't mean non-neglible either.

[Tainnor]

It's still a stretch to say that the virus is "harmless" to children.

But that's beside the point. The real point about children is that they can spread the virus just as well, even when they don't get sick - especially since it's also really hard for at least smaller children to keep distance or wear masks.

[tghw]

You might want to read this one: https://www.forbes.com/sites/leahrosenbaum/2020/08/19/why-t-...

[gloriosoc]

I read that and I find it pretty infuriating. It has a lot of fake and unsubstantiated science claims by the author.

[tghw]

Also, the JHU map is a poor indicator, as they are clearly basing the colors on suspect data, as in this case in Nebraska, which apparently had negative new cases yesterday.

[1] https://www.dropbox.com/s/uakm0cfgn2hv94r/Nebraska.png?dl=0

[gloriosoc]

Oh sometimes that happens because states make mistakes in reporting and want to correct them. I would guess that's the case here. It also happens in the other direction- big spikes are sometimes a backlog of cases all reported at once.

[tghw]

While true, that map and a photo of an outdoor space with people in it are poor pieces of data to hinge your entire argument on.

You completely failed to take into account people working from home, schools delaying opening and not having been in session since March or April, and all of the other measures that have been put in place to decrease transmission (masks, barriers, decreased social interactions, restaurant closings, other indoor spaces being closed, etc, etc, etc).

Your conclusion is flawed because you left all of these factors out of your analysis.

[gloriosoc]

I don't think this could explain the huge jump in cases and then decline post-reopening in Fl,Az, and LA. They aren't being more careful now than they were in early June. Disney world is open, people are outright refusing to distance or wear masks, the beaches are packed and yet we are seeing a drop in cases.

[rallison]

> They aren't being more careful now than they were in early June.

Source? This is a significant claim. Early June was a low point in cases, hospitalizations and deaths. Lots of states were at peak reopening around then, as things seemed to be on the right track.

For example, bars opened in early June in Florida. They closed on June 26th after cases started spiking.

Louisiana was similar. The state started reopening May 15th. Later in June, bars were then closed back down again, and a mask mandate went into effect.

In Arizona, the story is similar, with gyms, bars and movie theaters shutting back down in July after having opened in May.

What sure seems to be the pattern is: things open up, cases rise, things close back down, cases drop. I'm not so sure that your "they aren't being more careful now than they were in early June" statement is accurate, and I think this is causing you to misattribute the cause of the drops in cases.

[gloriosoc]

Mmmm You can see the timeline of orders that were put into place and the correlation. Here is Florida https://coronavirus.jhu.edu/data/state-timeline/new-confirme.... No mask mandate at all. Disney world is open. Beaches are open. The only order was bars are shut down. Without other distancing or masks, it's hard to believe that would stop spread.

[isabelc]

In Miami-Dade County in Florida, it's not only bars that are closed but all indoor dining is not allowed. Restaurants had opened for dining for a short while but that was banned again in July. And masks are required in public everywhere, even outdoors. And a strict countywide curfew has been in place since July.

[gloriosoc]

It's fixed now btw

[avremel]

This article in the Atlantic mentions possible herd immunity at < 40%.

https://www.theatlantic.com/health/archive/2020/07/herd-immu...

[tghw]

> Back in February, Lipsitch gave a very rough estimate that, absent intervention, herd immunity might happen after 40 to 70 percent of the population had been infected.

Which is actually a mischaracterization of what the previous article[1] said:

> Lipsitch predicts that within the coming year, some 40 to 70 percent of people around the world will be infected with the virus that causes COVID-19.

At no point does he mention herd immunity. So, no, he's not saying herd immunity at 40%.

[1] https://www.theatlantic.com/health/archive/2020/02/covid-vac...

[newen]

It's very hard to trust these low prevalance numbers when, for example, I know a few people who are close friends with people in medical fields who tested positive but they themselves didn't get tested but had mild symptoms. I myself had mild symptoms that I'm 99% sure is covid and didn't get tested.

[tghw]

Just because you and your friends weren't tested, doesn't mean the statistics are invalid. The link above was from random antibody testing and has a high confidence interval.

I've been sick twice during this time. Thought it had to be COVID, but two PCR tests and an antibody test all came back negative. Maybe the tests are flawed, sure, but it's far more likely I just had something else.