Those countries may not have hit "herd immunity" yet, that's the point. How do you explain Sweden? I know France has still considerable restrictions and mask wearing etc. Can this be explained by changed in human behaviors in those states above?
I doubt it.
Something else is happening, I think.
This thing starts, and looks bad, so we shut down and suppress it, but then start to reopen and it comes back in full force. And then, it slows down again, as with Sweden. No real changes in human behaviors of consequence.
I guess you could claim the protests largely dissipated.
Area under the curve ...?
I explain it primarily with behavior. Whether mandated or not, people DO respond to these case numbers by changing their behavior.
That's where Sweden came in. If they hadn't changed their behavior, their economy would have been largely unaffected. But it wasn't unaffected. They didn't forcibly lock down, but that doesn't mean they didn't voluntarily adapt.
People get complacent and start thinking "it's going away" so they get lax in their behavior, and then it spikes again and they say "oh, I guess it's still around."
Again these are all aggregates. This thing might have a R0 of 2.5-3.0 if no mitigating behaviors are undertaken, but right now our behavior has it down closer to 1. When we get lax, it goes above 1, when we tighten, it drops below.
But as I said, anywhere you get a cluster of people close together, it spirals out QUICKLY in that cluster. That wouldn't be the case if we had inherent immunity.
I don't think it's all too wild. There are some pretty credible sources coming up with these things, and then you have Sweden, and even Wisconsin.
Cases in Wisconsin have gone up by 60% over the past month, but testing has also gone way up in this period.
Positivity is around 5 percent here still.
What I think is unfounded conjecture is the idea that you threw out that 50% of people have had it, or that Cincy throws out that we have some sort of completely unknown inherent immunity in society that no scientist to date has identified.
To put it simply, the MUCH easier explanation is that mitigation has been primarily behavioral. This is even more strongly justified when you see that places/situations where the behavioral changes either can't or aren't continuing, you get spikes and clusters, which wouldn't happen if there was inherent immunity.