Post #1379: Omicron, the don’t-care wave of COVID-19

Posted on January 1, 2022

What is wrong with this picture?

Source:  Carnegie-Mellon University COVIDcast, accessed 1/1/2022

This post is more-or-less a followup on the just-prior post, where I found out that we’re now admitting as many people to the hospital under Omicron as we did at the peak of the Delta wave.  We’ve managed to offset the lower virulence of Omicron with a vastly higher number of cases.  And the peak of the Omicron wave is nowhere in sight.

And, near as I can tell, other than hospital workers, people just don’t seem to care.  Which I find odd and irrational.  But it is what it is.

And that’s the topic of this post.

Along with COVID in children.  For which, I will say up front, Omicron does not appear to disproportionately affect children.  In Virginia, there was no change in pediatric share of COVID-19 cases over the month of December.

Background:  The shifting situation

People tend to fuzzy-think their way through a lot of situations in life.   They get hold of an idea that sounds good, and they don’t bother to take a hard and objective look at it, as long as they are comfortable with it.

By now we’ve all heard that Omicron is less virulent than Delta.  And so, I guess we are each, individually, thinking that we’re in some sense a lot safer now with Omicron than we were with Delta.

Let’s call that a warm-and-fuzzy-thinking view of Omicron.  It’s not so bad, on a per-case basis.  Lot better than Delta, say, which had a reputation for virulent infections.

But those of us capable of doing simple math reach a different conclusion.  My likelihood of ending up in the hospital under Omicron is now just about exactly what it was at the peak of the Delta wave.  That’s because my odds depend on two factors:

  • Odds of hospitalization = odds of infection x odds of hospitalization, once infected.

For sure, the second term is lower under Omicron than Delta.  Maybe one-third as large.  But give it another couple of days, and the odds of infection term will have more than offset that.  The current situation is best described as:

  • Odds of hospitalization, Omicron = 3*Delta X (1/3)*Delta
  • Odds of hospitalization, Omicron = Odds of hospitalization, Delta.

Oh, and cases are now doubling roughly every week.  And two doses of vaccine does almost nothing to prevent Omicron infection.   And reinfections are common among those who have already recovered from some prior variant.

And nobody seems terribly concerned.

Doesn’t that strike you as odd?

And yet, nobody seems terribly concerned

Let me just start with my home town.  As documented in Post #1377, three days ago they were blithely going to shut down a drive-through COVID-19 testing center in town.  Which, as it turns out, would have reduced local testing capacity by about a third.  (Although I am almost sure they didn’t bother to figure that out first.)  Based on news reports, Town officials appeared absolutely unconcerned about the impact that might have.  Only after significant citizen protest did common sense prevail, and the Town bureaucracy agreed to allow the testing site to remain open another month.

In my state of Virginia, it looks like the Governor’s emergency orders all ended with the end of 2021.  The only mask requirements are that masks must be worn in schools and on public transportation.  (I’m pretty sure the second one is a Federal requirement).  There’s no talk of (e.g.) limiting occupancy of bars and other high-transmission-risk areas.

Schools?  Again, I’m seeing no talk of virtual schooling in my area, for grade schools.  My daughter’s college (and many others) are going to require a booster shot for return to campus, for those eligible, and will require mask use in commons areas.  So far, it doesn’t look like they will require a negative COVID-19 test prior to return to campus.

And, noted at the top of the post, about a third of people who were wearing masks last winter can’t be bothered to put them back on this winter.

In short, almost no COVID hygiene will be enforced, aside from masks in schools (in Virginia, anyway).    Private academic institutions seem to be moving to a standard of masks and booster shots.  Beyond that, a lot of people aren’t going to undertake that hygiene voluntarily, and it sure looks like, with a few exceptions, there isn’t a whole lot of lifestyle modification going on.

Against a background where new cases are doubling every week.

I wonder what’s going to happen when everybody goes back to school?

A quick look at pediatric COVID cases.

Let me start by reminding you of what happened when U.S. kids went back to school this past fall:  Nothing.  For sure, nothing happened in Virginia, because I tracked that pretty carefully (e.g., Post #1268).  And, I think that with a few exceptions in the upper Midwest, pretty much nothing happened anywhere.  There was some above-average spread among sports teams (a high-risk group due to close physical contact).  A few outbreaks.  And not much else.

I’ve never found a timely national data set showing new COVID-19 cases by age.  CDC will give you that information with a couple of weeks lag, based on their own case-reporting system.  But when cases are doubling every week, that might as well be a couple of years.

So I’m turning to data from Virginia.  We’re a middle-of-the-road state, we currently have 118 new COVID-19 cases / 100K / day, and the state Department of Health provides excellent, timely data, including a breakout of cases by age.  The data source is this file, updated to 12/30/2021.  If there’s been some big shift in COVID-19 cases, it should show up here.

There has been no change in pediatric share of cases under Omicron, in Virginia.  As Omicron has begun displacing Delta in Virginia, there has been no noticeable shift in the share of new COVID-19 cases that is for pediatric (under-age-18) cases.

Source:  Calculated from Virginia Department of Health data cited above, accessed on 1/1/2022.

Not quite tongue-in-cheek, I’ll also provide this information as a service to parents of Virginia school-age children who may be worried about the impending return-to-school.

Source:  Calculated from Virginia Department of Health data cited above, accessed on 1/1/2022.

There are about 1.7M persons under the age of 18 in Virginia.  There was one COVID-19 death in December.  Over the entire course of the pandemic, there have been 12 pediatric deaths attributed to COVID-19, for a risk of death, for persons under age 18, of about 0.0004% per year.

That said, this is is non-negligible risk of hospitalization.  Combining Federal and State data for December, the COVID-19 case hospitalization rate for the pediatric population of Virginia was just over 1 percent.  So while risk of death is vanishingly small, risk of being hospitalized with COVID is currently about one-in-100 diagnosed pediatric infections, in Virginia.

But what about rising pediatric hospitalizations under Omicron?

In the U.S., as was seen in South Africa and elsewhere, it looks like there’s a significant increase in hospital admissions for children with COVID-19.  I did the graph just a few days ago, for the U.S.:

Source:  Calculated from U.S. DHHS Patient Impact and Hospital Capacity by State Timeseries

(I would love to redo this now, for Virginia, but the pediatric admissions data are too sparse.  In a typical December 2021 day, pediatric (under age 18) admissions for COVID-19 were in the single digits.  The resulting pediatric fraction of cases is all over the map.)

My most plausible answer for the apparent increase in pediatric admissions for COVID-19 is that it may be due to persons admitted with, but not for, COVID-19.  I went through this distinction in Post #1351, principal versus secondary diagnosis of COVID-19And maybe that shows up disproportionately in the pediatric population because the COVID hospitalization rate is so low?

And yet, every time I try a back-of-the-envelope calculation, I’m not sure I can justify that.

But I will note, as a matter of fact and not speculation, that pediatric admissions rose as a fraction of total at the peak of the Delta wave as well:

So, at the very least, this isn’t the first time this has happened.  And the speed of increase in the pediatric share appears to correlated with the speed of increase of total cases in the population.

So I have to speculate that this “increased pediatric share of admissions” might be an artifact of the high prevalence of COVID-19 in the population.  That, somehow, those “stray” cases of people hospitalized “with-but-not-for” COVID disproportionately affect pediatric admission counts.

I just can’t find a way to prove it.  But at least now I can tell you that this happened in the last COVID-19 wave as well.

Let us all now collectively hold our breath as children everywhere return to school next week.  Given how fast Omicron moves, by mid-January we’ll know whether that’s a mistake or not.