The U.S. is now below 14 new COVID-19 cases per 100K population per day, down 37% over the past seven days. We now have 18 states with new-case rates in the single digits. There’s some evidence of a modest slowdown in the rate of decline in the states with the earliest peaks and lowest current rates, but not much of one.
This continued rapid decline in new cases seems almost unique among first-world countries that had a significant Omicron wave. That’s great for us, but I have to wonder what makes the U.S. so different from the rest of the world, for the end of the Omicron wave.
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 3/8/2022, 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 first chart above shows where we stand today, compared to the entire Omicron wave. The new case rate is now 5% of what it was at the peak of the Omicron wave.
The second chart illustrates the slight slowdown in the decline in cases that began circa 2/22/2022. And yet, while there’s a little kink in the line at that point, it’s not as if things have slowed further. We went from a stead 40%+ weekly decline, to a stead 30+% weekly decline.
Charts 3 and 4 are my attempt to figure out where we’ll end up — what will be our “endemic” level of COVID-19. All I can say is that we’re not there yet. The third chart shows the states that peaked earliest, the fourth chart shows the states that had already achieved single-digit rates as of 3/4/2022. As with the U.S. as a whole, there’s some evidence of a slowdown in decline — the data deviate from the straight line I’ve drawn on those log-scale charges. But not much of a slowdown.
The international situation and BA.2?
Let me end this by illustrating how different the U.S. experience seems to be from most other countries. (I focus here on large English-speaking countries because I can read their government websites if I want to find out more, see below).
Here’s the U.S., Australia, Canada, and the U.K., below. Just a glance at the charts tells you that the U.S. graph is qualitatively different from the rest. From top to bottom:
- In the U.S., cases continue to fall rapidly.
- In Australia, new cases are rising slowly.
- In Canada, although it’s harder to see, cases are also rising slowly.
- In the U.K., cases are clearly going up.
I took a brief look at the U.K. and found just a couple of things.
First, in the U.K., the more-infectious son-of-Omicron (BA.2) has became the dominant strain around the third week in February. As of 2/20/2022, BA.2 accounted for about 52% of all new cases, up from 19% on 2/6/2022. (That’s from this weekly report published by the government of the U.K.)
Second, the U.K. had a surge in cases in “care home” back in December. (I believe we would call those “assisted living facilities” in the U.S. Those are residence for individuals who need help with the normal activities of daily living, but who do not require the level of care provided in a nursing home.) But the U.K. government has determined that BA.2 is no particular threat to the care home population, as long as those people are vaccinated.
In short, the only thing I can pin down about the current situation in Great Britain is that the increase in cases is occurring at the time that the more-infectious BA.2 has become the dominant strain.
The CDC just published its weekly update for COVID variants in the U.S., and they now estimate that BA.2 accounted for 12 percent of new U.S. cases as of the week ending 3/5/2022.
What’s more interesting is that the BA.2 share of new cases continues to double every week. That’s up from about 6% a week ago, and just over 3% two weeks ago.
(Separately, in Canada, BA.2 accounted for 11% of new cases as of the week ending 2/13/2022, per this Government of Canada report. That would put Canada several weeks ahead of the U.S. in terms of BA.2 as a fraction of new cases at that point. But the rate of increase was quite slow. BA.2 share of new cases appears to be doubling every month or so there, compared to every week or so on the U.S.
(For Australia, as far as I can tell, the Government of Australia does not track BA.2 as a variant of concern. At least, not in these official reports. So there appears to be no national estimate available. Some of the individual states do track it, but again, I couldn’t find any systematic analysis. I found one snippet of reporting suggesting that BA.2 has become the dominant strain in parts of Australia. For what that’s worth.)
There’s no way of knowing whether the U.K.’s current uptick is a result of the spread of BA.2, or whether it’s just a coincidence of timing. But in any case, at the current rate of growth, it will only be another week and a half before BA.2 becomes the dominant strain for new U.S. cases. If we see no pause in our decline, at that point, we can be fairly sure that BA.2 is not going to be a problem for the U.S.
If we see a pause in the U.S. decline that point, we’ll have to rethink things a bit. Near as I can tell, nobody is suggesting that BA.2 will lead to another large wave of COVID. But everybody seems to agree that it will definitely slow down the rate of decline in cases as we transition from the Omicron wave to “endemic COVID”.
