There’s a small visible uptick in the new case rate, but the fact is, rounded to the nearest whole number, the U.S. stands at 9 new cases per 100K population per day, unchanged for more than three weeks now.
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 4/9/2022, 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
Probably the main reason to make little or nothing of this most recent blip is that there’s no longer any reason to expect a surge of cases. The worry for the past few weeks was son-of-Omicron (BA.2), which is more infectious than standard Omicron. That was spreading rapidly, and might have triggered a second Omicron wave. But that already accounted for about three-quarters of U.S. cases as of last week. Given the lags in reporting, BA.2 arguably accounts for more than 90% of current infections. And so far, nothing has happened commensurate with that change.
On the other hand, arguing against that is the decline in immunity that is now occurring as vaccinations and prior infections age. The rapidity of decline depends on what outcome you are talking about. The decline in protection against any infection appears pretty substantial. By contrast, the decline in protection against hospitalization and death appears much smaller.
Source: Calculated from data from the CDC COVID data tracker.
The data above are observational data (not a randomized controlled trial), so they may reflect both the effect of the vaccine and any differences in behavior or exposure between the vaccinated and unvaccinated groups. That said, the trend is unmistakable. A few weeks after the booster shot, those who got the booster were hospitalized at 3% or 4% of the rate of the un-vaccinated. By the time you get to five months post-booster, the hospitalization rate for the boostered population had risen to 15% or more of the unvaccinated population.
(There’s an important subsidiary issue here, in that you see a lot of internet chatter about how Omicron has gotten less severe, because we’re not seeing a lot of hospitalizations and deaths from recent superspreader events. To the contrary, what we’re probably seeing is that vaccination was a requirement for attendance, as with the recent Gridiron Club dinner. I haven’t looked up the data, but I’m pretty sure the case hospitalization and case mortality rates haven’t declined for the un-vaccinated population.)
I could not find the data on the CDC COVID data tracker to draw the equivalent weekly curve for likelihood of any infection. But based on the monthly data, protection against any infection, a few months out, is less than protection against hospitalization. For example, on the chart above, where the 65+ population was 15% as likely to be hospitalized as the unvaccinated, they were about 30% as likely to have any infection, as of February 2022. That’s again based on the CDC COVID data tracker.
Worse, we now know that a second booster only increases antibody levels briefly, based on recent observations from Israel. Those antibodies are the key to protection against any infection (whereas other, slower-acting parts of the immune system come into play when it comes to preventing an infection from resulting in hospitalization or death).
The upshot is that what you see above is pretty much as good as it gets. At least until there’s some miracle-of-modern-medicine that performs better than the existing MRNA vaccines. Immunity fades over time, and fades rapidly enough to have a material effect on your odds of infection and severe outcomes. That’s just the way the world is.
On yet another hand, one reason to make nothing of this tiny change is that we haven’t yet seen a sustained rise in reported new cases in Canada. Throughout the pandemic, the U.S. and Canadian curves have qualitatively similar (except for the impact of holidays, e.g., U.S. Thanksgiving versus Canadian Thanksgiving).
Source: Johns Hopkins data via Google search
On the fourth hand, we have seasonality as a reason to make little of this uptick. Assuming this coronavirus behaves as it did for the past two years, and behaves like most other coronaviruses, seasonal factors should be acting to push the new case rate down.
On the fifth other hand, it always pays to listen to the smartest person in the room. Which, in this case I would say is Dr. Fauci, Director of the National Institute of Allergy and Infectious Diseases, a division of NIH. He isn’t talking about any near-term resurgence. He’s talking about what’s likely to happen this fall:
Source: Google news, accessed 4/9/2022
I interpret that as saying that he has more-or-less dismissed the possibility of a significant resurgence in cases before then. And surely he is privy to whatever information exists on the current state of the pandemic in the U.S. If Dr. Fauci is focused beyond the near-term, likely we should be as well.
(On yet a sub-other-hand, Dr. Fauci attended the Gridiron Club banquet at which the most recent super-spreader event occurred. From which I’d have to guess that the development of a superspreader event there was a surprise to the experts. Although, honestly, when I ran the numbers, the likelihood of having somebody there who was infectious was fairly high, even if all attendees had to have been vaccinated.)
The final other hand is the potential for a massive uptick in un-reported cases in the U.S., as appears to be the case in the United Kingdom (Post #1748). That would hide a resurgence of cases. No doubt that a lot of positive at-home testing is going unreported. But what we haven’t seen here is any uptick in hospitalizations. As with Great Britain, if the true underlying count of cases were rising rapidly, that would show up almost immediately in the hospitalization rate. So I think we can dismiss that as a possibility.
Source: CDC COVID data tracker, accessed 4/9/2022
Best guess: All hands considered, my best guess is that what we have now — some modest ups and downs in the observed new case rates, but nothing overwhelming — is pretty much what we’re going to see until the fall.
Right now, the slow fade of immunity and slow relaxation of the remaining COVID-19 hygiene are pitted against the natural seasonality of COVID-19. But this fall, all those factors will be pushing in the same direction. Immunity will have continued to fade. (And I’d bet that any Federal push for fourth boosters at that time will be met with a yawn, until the winter wave starts.) Mask wearing in public indoor spaces will have become an unusual behavior in most parts of the country. And the inherent seasonality of COVID — not really different from flu — will come into play.
So I think I’m with Fauci on this one. Right now, we have a tolerably low new case count, new hospitalization count, and death count. Not hugely different from what we’d see for flu, in a normal flu season. The next test will be this winter. That’s the point at which we’ll see if we’ve gotten better at dealing with this, or not.
In case it’s not obvious, my plan is to get my fourth booster late this fall. I’ve purposefully not gotten it now, because right now, the low level of new cases in the community suggests relatively small risk. Whatever immunity bang-for-the-buck I’m going to get out of a fourth shot, I want that to be maximized in December/January, which is when COVID-19 cases have peaked in the U.S. for the past two years.
