I can’t get into this article on this computer. But, I see some misinterpretation here. “On the order of about 5%” is a VERY hazy estimate, ie., a 10:1 range. And even that’s prefaced with “may”. The tweet is next to meaningless.
The sampling itself is supposed to reflect the entire population. How does the tweeter get from actual data(!) in a hotspot(!) of 2.49-4.16% infected to 5% nationally? When a hotspot is surely going to be considerably higher than the general population? By being very sloppy, that’s how. Then the article author confuses the number of diagnosed, which is not taken from the general population.
OTOH, COVID-19 is clearly contagious enough that eventually much of the population will be infected, barring a good vaccine. Whether lasting immunity is conferred is uncertain. I have serious doubts about it for mild and asymptomatic cases.
In truth, the number of infections is at this point less important than the rate of hospitalizations. Even for “just the flu”, getting hospitalized gets one into fairly grim CFR (HCFR) numbers. It’s pretty clear that had NYC locked down a week later, it would have had a healthcare system disaster, even with all the Federal help that could be brought to bear.
I don’t know what tweet you’re talking about, as this is a summary from Fox News of the initial results of a study in the SF bay area. USC and LA county are underway with similar work this week.
All is preliminary and we should expect results to vary as additional data are collected.
I agree with the rest of the points that you raise. That and 5 bucks will get you a cup of coffee though!