Category: COVID through 2022

All my various postings tracking the COVID-19 pandemic through the end of 2022.

Post #1439: The news reporting I’ve been hoping not to see.

 

This showed up on Google News today:

Source:  Google News, accessed 2/20/2022.

I wouldn’t normally pay attention to that.  “The news” presents you with a constant stream of scare stories.  Any time there’s some credible source, and a scary story, you’re going to see it, whether or not there’s much to it.

I wouldn’t normally, except that I’ve been waiting to see something like that show up. 

That’s due to the graph I’ve been updating almost daily.  This one, showing how hospitalizations, deaths, and cases have trended since the peak of the Omicron wave:

Source:  Calculated from CDC COVID data tracker data.  Case death rate is deaths divided by new cases from two weeks’ prior.

Something ain’t right about that.  If there were no change in the underlying COVID-19 variant, and no change in data reporting, it ought to look just like the peak of the Delta wave.  Like this, with all the lines in sync:

Source:  Calculated from CDC COVID data tracker data.  Case death rate is deaths divided by new cases from two weeks’ prior.

But instead, reported cases have fallen a lot, hospitalizations not so much, deaths even less (with a two-week lag built into what I’m showing above).  And as a result, the case hospitalization rate and case death rate for Omicron appear to be going up.

Source:  Calculated from CDC COVID data tracker data.  Case death rate is deaths divided by new cases from two weeks’ prior.

On paper at least, the case hospitalization rate for Omicron is just shy of 7 percent, which is what it was under Delta.

Up to now, I’ve been happy to fuzzy-think my way through this and say, well, that’s probably due to missing positive cases.   Maybe, all of a sudden, starting with government handout of free tests, home testing is really taking off.  And that’s suppressing the official case count.  Which then, on paper, raises the apparent case hospitalization rate.

But all along, I have to say that the magnitude of that effect had to be pretty large.  Maybe implausibly large.  I mean, if the case hospitalization rate has nearly tripled, doesn’t that mean that we’d have to be missing two-thirds of cases?  But if we were, wouldn’t that mean a much steeper descent in the case counts?

In other words, I couldn’t quite make the math work out. So I waved my hands and said, must be due to some missing cases.

The other hypothesis is that Omicron actually is getting more virulent.  Maybe one of the two growing sub-variants of Omicron in the U.S. is, for reasons unknown, more virulent than the original.

And, of course, it’s not as if those are mutually exclusive explanations.  Plausibly, what you’re seeing could be due to some mix of the two.

The upshot is that I’ve been keeping an eye peeled for any indication that the either of the two newer strains of Omicron might be more virulent.  I noted that, for reasons unknown, the CDC began breaking out all three strains as of the last round data.

Source:  CDC COVID data tracker.

That said, I still can’t make the numbers work out.  The peak of the Omicron wave was 1/16/2022.  As of the last reading from CDC (above), BA.2 was still just a tiny fraction of all cases.  BA.2 could not possibly be causing a huge upswing in the case hospitalization rate yet.

And that makes me wonder about BA.1.1.  But so far, nobody has mentioned anything about that being markedly different from the original Omicron strain B.1.1.529.

(BA is the alias for B.1.1.519, the original strain of Omicron.  Each dot in the name stands for the next generation of mutations.  BA.2 is the second son of Omicron.  BA.1.1 is the first grandson of Omicron. )

Finally, in Post #1400-1, I addressed an old and thoroughly incorrect notion, that viruses will get “weaker” as they mutate.  You will still see that repeated from seemingly responsible news sources.  Search that post for “soundly debunked” to see modern scientific thinking about this.

Evolutionary pressures force successful new variants to be highly contagious.  That’s how they displace the prior existing strains.  By contrast, the virulence of each new strain is more-or-less random.  It’s based on whatever other mutations happen to “hitch a ride” on the set of mutations that allows a new strain to be more infectious than the older one.

As I stated in Post #1400-1 :  We got lucky with Omicron.  Lucky that it was far less virulent than the Delta strain it displaced.  This, in a pandemic where good luck has not exactly been abundant up to now.

The bottom line is that I don’t really understand what’s driving the rising case hospitalization rate.  We’d have to be missing an enormous number of cases for that to be due to missing cases alone.  But BA.2 is not yet prevalent enough to have had much of an impact on case severity.

That said, I think this issue of severity is well worth keeping an eye on.  If what ends up as “endemic Omicron” is both highly infectious and highly virulent, that means we’ll be living in a somewhat different world, going forward, relative to one where the original, milder Omicron strain dominates.

Post #1438: COVID-19 trend to 2/18/2022, finishing out the data week, and a table of the crude odds of exposure.

 

Still no surprises.  The U.S. now stands at 34 new cases per 100K population per day, down 41 percent in the past seven days.

COVID-19 hospitalization and deaths are falling much more slowly than reported new cases.  My best guess remains that recent growth in home testing has created a divergence between reported new cases and new hospitalizations and deaths.  But there’s no way to prove that directly, and that implies that there is a very large volume of home testing going on.

Continue reading Post #1438: COVID-19 trend to 2/18/2022, finishing out the data week, and a table of the crude odds of exposure.

Post #1437: COVID-19 trend to 2/17/2022, no surprises.

 

U.S. new COVID-19 cases fell to 35 per 100K population per day, down 45 percent in the past seven days.  Judging from the continuing decline in cases in the states that led the Omicron wave, we can expect this to continue for at least another week or two.

For all intents and purposes, I could just keep putting up the same graphs day after day, and I don’t think you’d be able to tell the difference.

Continue reading Post #1437: COVID-19 trend to 2/17/2022, no surprises.

Post #1436: COVID-19 trend to 2/16/2022. One month post-peak, cases are back to where they were before Omicron.

 

The U.S. is now down to 38 new COVID-19 cases per 100K population per day.

In some sense, we’ve now completed the U.S. Omicron wave.  Today’s case count matches what it was at the start of the Omicron wave, almost two months ago to the day, on 12/17/2021.

And we’ve reached that milestone exactly one month after the peak of the wave on 1/16/2022, at which point the U.S. was seeing almost 250 new COVID-19 case per 100K population per day.

The upshot is that the U.S. Omicron wave was weirdly symmetric.  It was one month straight up, then one month straight down.

The only remaining questions are a) is that an accurate reflection of new cases, and b) what happens next?

Continue reading Post #1436: COVID-19 trend to 2/16/2022. One month post-peak, cases are back to where they were before Omicron.

Post #1434: William and Mary COVID trend to 2/14/2022

 

Source:  Calculated from William and Mary COVID-19 dashboard.  Virginia new case rate calculated from Virginia Department of Health data and Census population estimates by single year of age.

This week’s new-case number was an unpleasant surprise.  The rate of new cases among students at the Williamsburg campus is now more than three times the rate for 18-24 year olds in Virginia as a whole.

Even with the understanding that W&M students may be more likely to get tested, this seems like a significant difference.  As importantly, while new cases are trending down in Virginia as a whole, they appear to be trending up at William and Mary.

This is also completely at odds with a superficial reading of William and Mary’s 2/15/2022 email to parents (Subject:  [parents-l] W&M COVID-19 Updates), where they state that:

 "Currently, many of these metrics are trending favorably, ... we are encouraged that we are in a much better position than we were in early- to mid-January."

That’s a weirdly ambiguous piece of text.  You have to stop and realize that by “we”, they meant the U.S.A., and not William and Mary in particular.  Return to campus didn’t occur until the end of January, and William and Mary’s metrics are trending unfavorably.

To me, to the extent that anyone continues to worry about the health consequences of COVID-19, this current increase seems to be well worth tracking.  New case rates are falling throughout the country, but not at William and Mary.

So, what’s the issue with W&M students that is not present in that age group for Virginia as a whole?

If I return to that 2/15/2022 email, and as with that line above, try to read past the ambiguities and try to read between the lines, I have a pretty good guess as to what the main problem is.  Emphasis mine:

"One of the data points that does appear to be different this spring is the number of individuals being identified as close contacts. Given the high transmissibility of the Omicron variant, I encourage you to socialize in small groups with your core friends and colleagues and to meet outdoors whenever possible. For those that would like them, faculty and staff may order masks from the facilities management warehouse and students may pick up additional masks from the Sadler Center information desk. "

When I step back from all that polite talk, and focus on “socialize” and “masks”, my best guess is that the problem now is the exact same problem they’ve had in the past.  Probably, students have gone back to holding unmasked parties. 

That was the issue at the first return-to-campus outbreak under COVID.  That was the issue for the St. Patrick’s day outbreak last year.  It would be completely unsurprising if that were the issue now.

That’s purely guesswork on my part, but all the pieces seem to fit.

But why the seemingly nonchalant attitude on the part of the William and Mary administration?

Return briefly to last year’s St. Patrick’s day outbreak (Post #1099).  I think everybody took that one fairly seriously.  That outbreak generated 120 new cases in 11 days, or a rate of 11 new cases per day.  So, the current rate of daily new cases is now roughly what it was during the St. Patrick’s Day outbreak last year.

But while the case count is about the same as St. Patrick’s Day 2021, the health risks are vastly lower. That’s due to vaccination plus a milder strain of COVID-19.  CDC data show that full vaccination remains roughly 80% effective at avoiding hospitalization from Omicron, and that vaccination plus booster is is about 90% effective.  (You’d have to download the data from the references on the CDC vaccine effectiveness web page to find that.)  On top of that, the crude hospitalization rate for Omicron is about one-third that of prior variants.  All told, that’s something like a (1/(.2 x . 33)) = 15-fold reduction in health risk, per case, compared to the situation last year.  (No one has the data on significant health risks other than hospitalization, but I would expect all significant risks to be reduced roughly in proportion to the hospitalization risk.)  And so, the current 12 cases per day presents about the same population health risk as one new case per day would have, around this time last year.

With that in mind, it now makes more sense that William and Mary is dancing around the issue of parties and masks, now, when they took a lot firmer stand during prior periods that had roughly the same daily new case.

Again, guesswork on my part.  I can’t read their minds as to why the wording regarding socializing and masks is now so oblique.  But it makes logical sense.

All I can say for sure is that the metrics at William and Mary are not trending favorably.  COVID-19 may be approaching endemic status in a handful of areas, but the William and Mary campus is not yet one of them.  The seems well worth keeping an eye on for a while longer yet.

FWIW, I’m now of the opinion that for your average boostered individual, the health risk from COVID-19 now, in Virginia, is no higher than the risk from typical seasonal flu (explained here or here).  So I’m not trying to be alarmist at all.  I don’t see a huge risk here.  I’d just like to see the counts at W&M going down, as they are everywhere else.

Post #1433: COVID-19 trend to 2/14/2022, maybe the beginning of a slowdown.

 

The U.S. now stands at 47 new COVID-19 cases per 100K population per day, down 81% from the peak.  Only two states remain above 100 per day (KY, ID).  The majority of states are below 50; five states are below 25 new cases per 100K per day (NY-NJ-CT, MD-DC).

Cases are down 39% in the past seven days, a bit slower than in the recent past.

As I said in recent posts, I think the decline in the official new case count is being exaggerated, probably as a result of the growing use of home testing using over-the-counter rapid tests.  As an alternative measure that should be unaffected by that, new COVID-19 hospitalizations are down 55% from the Omicron wave peak. Continue reading Post #1433: COVID-19 trend to 2/14/2022, maybe the beginning of a slowdown.

Post #1432: COVID-19 trend to 2/11/2022: Great news, the case counts are wrong.

 

The official count of U.S. new COVID-19 cases per 100K population per day now stands at 57, down 42% over the past seven days.  The U.S., unlike any other country, is seeing an extended, uniform, smooth decline in new case counts, with no slowdown in sight.

See caveat section below before you get too excited about that.

Continue reading Post #1432: COVID-19 trend to 2/11/2022: Great news, the case counts are wrong.

Post #1431: COVID-19 trend to 2/10/2022. The trend is good. Maybe too good. Revisiting the home-testing issue.

 

The U.S. now stands at 63 new COVID-19 cases per 100K per day, down 43 percent in the last seven days, and down almost three-quarters from the 1/16/2022 peak of the Omicron wave.

Just eight states remain about 100 cases / 100K population per day, and no states exceed 200.

So far, there is still no clear sign of any letup in the rate of descent.  That makes the U.S. experience unusual (possibly unique) by international standards. 

Could this lengthy, steady, and extremely rapid descent reported positive cases be a consequence of some sort of problem with the data, such as the rise of in-home testing?

Turns out, the answer to that is yeah, it just might.  Hospitalizations and deaths are not falling anywhere near as fast as reported cases.  Best guess, that only started to happen in early January.

Continue reading Post #1431: COVID-19 trend to 2/10/2022. The trend is good. Maybe too good. Revisiting the home-testing issue.

Post #1430: COVID-19 trend to 2/9/2022, Omicron nears flu-like risk for boostered individuals.

 

The U.S. now stands at an average of 70 new COVID-19 cases per 100K population per day.  That’s down 42% in the last seven days. No states are above 200 cases / 100K / day; 43 states are below 100.

The rate of decline is slowing, just a bit, but the rate of nuttiness remains constant.  Apparently, large swaths of America are shocked, shocked to find out that in response to low current risk and rapidly falling cases, governors of many states are dropping mask mandates.  E.g., this reporting, attributing mask mandate repeals to pandering politicians.  I wonder what they think the alternative would be?  Masks forever?

In fairness, much of the reporting has it right.  E.g., mandates fall as we approach normality.  Mandates are eased in response to lower infection and hospitalization numbers.

(And let me contrast dropping a mask mandate, where, with forethought, public health officials make some reasoned judgement regarding risk to the public, versus what we’re in the midst of doing in Virginia, which is initiating a free-for-all regarding in-school mask use, based on a fact-free campaign promise made by the governor about half-a-year ago, done with no reference to current conditions, no reasoned assessment of risk, and no clear guidance to schoolchildren.  We may eventually end up in the same maskless place.  That said, you can reach the ground floor of a skyscraper by walking down the stairs or jumping off the roof.  It’s smarter to have a government that takes the stairs.  We have one that can’t even acknowledge that the stairs exist.)

In this case, this blog was only a couple of days ahead of popular press reporting (Post #1426, 2/7/2022).  I’ll chalk up the short lead time to the speed with which Omicron cases counts continue to fall.

As a prelude to my next post, just how low are current risks?  CDC has now put up a very nice summary of what is known about vaccine effectiveness, as part of the CDC COVID data tracker.  Using (what I believe to be) clinical trials data, they estimate that the three-shot vaccine regimen is about 90% effective in preventing hospitalization from Omicron.

With that new information in hand, and accepting that as hard data, right now, the average vaccinated and boostered American faces about the same risk of hospitalization from Omicron as from flu in a typical flu season.  That’s how low risks have fallen, from the combination of low case severity, plummeting case numbers, and an effective three-shot vaccine regimen.

If that’s true, then why are COVID-19 hospitalizations (~12,000/day) higher than typical flu season hospitalizations (~2,100/day)?  Almost all the Omicron hospitalizations are among the unvaccinated, followed by the less-than-fully-boostered. Even now, this remains mainly a pandemic of the unvaccinated.

Finally, this is not new.  COVID-19 risk has temporarily dipped below typical flu risk before.  Your risk from COVID-19 falls to a low level every time COVID-19 new case counts get low enough.  Late last summer, case counts fell low enough that the average fully-COVID-vaccinated American faced lower hospitalization risk from COVID-19 than from typical seasonal flu.  The only difference now is that Omicron is much less virulent.  We now obtain that flu-equivalent risk level, for the fully vaccinated-and-boostered, at a fairly high Omicron case count.

Details follow.

Continue reading Post #1430: COVID-19 trend to 2/9/2022, Omicron nears flu-like risk for boostered individuals.