The U.S. is now at 16 new COVID-19 cases per 100K population per day, down 30% in the past seven days.
We now have eight states with single-digit daily new case rates. That’s nice. But what’s nicer is that rates continue to fall at a rapid clip, even in those low-rate states. This suggests that whatever our “endemic” level of Omicron is, it’s likely to be low.
As with just about everything else about this pandemic, I don’t think anyone would have predicted that. Certainly not based on the extremely contagious nature of Omicron.
And, to be clear, we’re not seeing the same thing in Europe or Australia. At least, not yet. So this doesn’t appear to be any intrinsic property of Omicron, but somehow depends on the circumstances.
Data source for this and other graphs of new case counts: Calculated from The New York Times. (2021). Coronavirus (Covid-19) Data in the United States. Retrieved 3/4/2022, from https://github.com/nytimes/covid-19-data.” The NY Times U.S. tracking page may be found at https://www.nytimes.com/interactive/2020/us/coronavirus-us-cases.html
The only point I’m trying to make on the table below is that new case rates continue to fall at a rapid (percentage) clip, even where the rates are already in the single digits.
In fact, we haven’t even yet reached the point where the lower-rate states are the slower-decline states. To the contrary, that “22%” on the bottom line shows that the rate of decline remains faster in the lower-rate states, on average, compared to the higher-rate states. (If I toss all the observations that I think are data reporting anomalies — WA, NV, IA, ME — the correlation is 40%.)
At some stage in the decline, that’s to be expected. After all, the only way to get to be a low-rate state on this chart is to have a rapid rate of decline in your cases.
But at some point, if there is some “bottom” to this — some minimum rate of daily new cases that will be our “endemic COVID” rate — then that will change. New case rates will stop dropping as states hit that low, final, “endemic” rate.
So far, that’s not happening in the U.S. If there is some low, low rate at which Omicron is going to linger in the population, well, based on the above, that’s got to be in the low single digits.
Otherwise, if there’s any rhyme or reason to which states appear where on that list, it escapes me.
On a positive note, I should mention the “outbreak threshold effect”, as described in Post #1137, 5/7/2021. At some point, if a virus gets thinly enough spread in the population, it can actually get extinguished purely as a matter of bad luck (i.e., probabilities). That’s particular true for a virus with a high “kappa”, one that tends to spread by having a relatively small number of people each infecting a large number of others, rather than by each infected person infecting one or two others. If, in an area, you get down to the point where there’s only one or two of those events happening every day, at some point, just as a matter of luck, both of them will eventually fail to happen, at the same time. That drops the new infection rate to zero, where it will stick unless new cases are introduced from outside the area. That’s the theory, anyway. COVID-19 is definitely a high-kappa virus, as these things are reckoned. So who knows, maybe we’ll get lucky.
Finally, I need to say that other areas are not seeing the prolonged and rapid decline in new case counts that we are currently enjoying in the U.S. Below, in the two log-scale graphs of new cases by continent, half the looks like the U.S., and half is seeing stable or only slowly-declining new case rates.
Source: Our world in data.
As with the list of states, if there is any reason for this, it’s not obvious to me. But it does show that what we’re observing in the U.S. states now is not some intrinsic aspect of Omicron, but must depend on the circumstances. Maybe the climate, maybe overall population immunity. Maybe the presence of cheaply available home testing. It’s impossible to say what the reason is, if any.
The overwhelming scientific consensus remains that COVID-19 will become endemic. Nobody really knows that for sure, but that’s certainly the best guess at present. Based on the official case counts, the U.S. appears to be headed toward the low single digits of new COVID-19 cases. If COVID is now a permanent part of the landscape, at least we’ll be stuck with it at a fairly low rate of incidence.
