Author: chogan@directresearch.com

 

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.

 

I’m going to continue to track Omicron for a while longer yet, at William and Mary.  William and Mary is only updating their data weekly so I guess I’ll post once a week, if there’s anything to write about.

I doubt that many will read these posts.  Most  W&M parents found out about this blog via a W&M-moderated Facebook group.  The moderators of that group have banned discussion of COVID-19, so I suspect that most on that group will never get back to this blog.

Enough said.  Most of the value-added here is that I keep track of the historical data.  That’s not available on the W&M COVID dashboard.

Based on two weeks of data, the new case rate at William and Mary seems fairly steady at 5 to 7 newly-diagnosed COVID-19 cases per day.

That most recent rate of 7-per-day translates to roughly 100 new cases per 100K students per day.

Contrast to Virginia as a whole:  That’s just a touch higher than the rate for 18-24 year olds in Virginia as a whole, which I estimate to be 77 / 100K / day, for the seven days ending 2/7/2022, based on Virginia Department of Health data.

Contrast to last semester:  That’s maybe four times higher than the peak post-move-in rate last semester.  After the initial post-return-to-campus wave had died off, the highest rate observed was 11 new cases in the week ending 12/10/2021.  That’s under 2 per day on average:

That said, Omicron has a much lower average severity than the Delta variant that was prevalent at the end of last semester.  For example, looking at the Virginia data, if I date the start of the Omicron wave to roughly 12/17/2021, then so far there have been zero deaths in the 18-24 age bracket, from Omicron, in the whole of Virginia.

If I had to sum it up, I would say two things.

First, there does appear to be some need for further vigilance.  COVID-19 has not disappeared from the campus.  That 100 cases per 100K per day rate is high by historical standards.  And I need to remind myself that these numbers didn’t just happen.  The relatively high new case rate occurred in an environment with fairly stringent COVID-19 hygiene in place.

That said, the rate at William and Mary isn’t much different from the rate for Virginians age 18-24 as a whole.  And once you factor in the much lower average severity per case, the health impact of the current case rate probably isn’t much different from the impact of Delta at the end of last semester.

In any case, the numbers are up from last year.  I see that as no cause for alarm, but no clear justification to relax, either.

Finally, I should note the obvious:  Pre-return testing seems to work pretty well at preventing a big return-to-campus outbreak.  This isn’t exactly a controlled experiment, but the one semester when W&M didn’t do pre-return testing, they ended up with a large number of active cases on campus, as shown in the last chart above.  The semesters when pre-return testing was required, that didn’t happen.