T. Ryan Gregory 🇨🇦 Profile picture
Nov 16, 2022 22 tweets 8 min read Read on X
I noted recently that claims about exceptionally high rates of RSV this year, caused by "immunity debt" and explaining the high number of children in hospital, is an empirical claim that requires data. Well, we now have this for Canada thanks to @Wikisteff (follow him btw!). 🧵
Here is a plot of RSV rates since winter 2013/2014. As you can see, it's a very regular seasonal pattern for all the years up to the start of the COVID pandemic. There was essentially no RSV two years ago when schools were closed (winter 2020/2021). Rates of RSV in Canada from...
And it's not just RSV. There was almost no flu or colds caused by other coronaviruses (not SARS2) two years ago either.

So, we can conclude two things right away: 1) mitigations worked extremely well and absolutely crushed respiratory virus transmission, and) the first assumption of "immunity debt" holds, namely that there was a season without kids being infected with RSV or flu.
BUT, look at last year. Winter 2021/2022 was a record season for RSV. It is simply not accurate that we are seeing three years' worth of RSV cases this year. RSV was back last year after many mitigations were lifted. Rates of RSV in Canada from...
Last year, there were lots of cases of RSV but hospitals were not overwhelmed like they are right now. This year, RSV season has started early but the case numbers are not exceptionally high yet. Still, many kids are in the hospital already.
So, this doesn't fit with the simple "immunity debt" hypothesis. Something else seems to be going on. Of course, high rates of severe infection without more cases is consistent with the "immunity theft" hypothesis in which past COVID infection impairs immune function.
But there is another interesting observation pointed out by @Prassas, namely that flu was NOT back last year the way RSV was. Is there something about RSV and flu co-infections that matters? Immunity debt to flu but not RSV? Is flu more severe this year?

We still don't know what exactly is happening. What is pretty clear, though, is that assuming that it's simply "immunity debt" after two years of no RSV infections is false in Canada. This is why we need to test multiple hypotheses and why we need data, not just-so stories.
In the meantime, we *know* that mitigations work against the viruses that are leading to kids becoming very ill and pediatric hospitals being overwhelmed. Whatever the explanation, the right thing to do *right now* is to reduce transmission of these viruses in children. #MaskUp
Again, huge thank you to @Wikisteff for the data sleuthing -- this is exactly what we need. Also, as he noted:

For a bit more on "immunity debt" vs. "immunity theft" (the latter being only a slightly modified-for-catchiness version of @FurnessColin's "immunity robbery").

Don't forget to check out this fantastic discussion on @TheAgenda. Note that a couple of the claims made by Dr. McGeer (three years of RSV all at once after two years without, this only being a problem with pediatric hospitals in Canada) are not accurate.

It bears noting that there *is* a mechanism by which COVID infection can impair defence against RSV.

journals.plos.org/plospathogens/…

frontiersin.org/articles/10.33…

mdpi.com/1999-4915/12/1…

nature.com/articles/s4142…

• • •

Missing some Tweet in this thread? You can try to force a refresh
 

Keep Current with T. Ryan Gregory 🇨🇦

T. Ryan Gregory 🇨🇦 Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @TRyanGregory

Apr 1
It's very important to be clear about what is happening in the Canadian election and how progressives need to approach it. 🧵

The LPC surge toward a majority is due primarily to a collapse of support for the NDP and Bloc, and much less so a drop in support for the CPC.

1/ Vote and seat projections for Canada.
Vote and seat projections for Ontario.
Vote and seat projections for Québec.
This means that the Libs are mostly picking up progressive voters who are planning to vote strategically to stop the Cons. They are not picking up huge numbers of "moderate conservatives".

Cons support is generally committed but Libs support isn't.



2/angusreid.org/canadian-elect…
The *winning strategy* for Libs is to make strategic voting by progressives as painless as possible by leaning *leftward*.

The winning approach for progressive voters is to make it clear they cannot be taken for granted and do not agree with rightward drift.

3/
Read 6 tweets
Mar 19
Thoughts on pandemics, inclusion, annexation, Indigenous issues, climate, genocide, and more and the connections I see among them. I fully acknowledge that I am writing this from a position of substantial intersectional privilege.

🧵

1/
I really hoped that the (ongoing) SARS-CoV-2 pandemic would inspire us to make meaningful, positive changes in society. Indeed, early on it seemed like privileged people finally understood what it was like to lack access to things we otherwise take for granted.

2/
Sadly, but perhaps predictably, we instead rushed back to the status quo as quickly as we could. If anything, things are worse now in terms of public health, accessibility and inclusion, and global health equity. Infectious disease has been actively normalized.

3/
Read 10 tweets
Mar 8
Please, stop making these terrible arguments in order to dismiss threats of annexation by the US. 🧵

1. "He's just joking, trolling, negotiating, or being Donald."

Clearly not. Stop it.

1/
2. "Trump can't just declare war on Canada."

He wouldn't bother and he doesn't need to. The last time the US formally declared war was 1942. See every US invasion or occupation since WW2.

2/
3. "The US can't invade because of the constitution / international law."

He doesn't care about either of those things. See everything he's currently doing.

3/
Read 10 tweets
Feb 17
I'm sure infectious disease minimizers are attributing the record-shattering surge of severe flu this year to "immunity debt". Let's think this through, shall we?

🧵

1/
1. Serious mitigations ended more than 4 years ago. Why would immunity debt only kick in now? And why wasn't 4 flu seasons without mitigations enough to repay whatever "debt" there was?

2/
We wrote this more than 2 years ago.

calgaryherald.com/opinion/column…
Read 12 tweets
Feb 16
🧵

Just to recap what is happening, since public health has gone AWOL:

* This is the worst flu season in 15 years. Not just number of cases but number of *severe* cases.

1/
* H5N1 ("avian flu") is getting further out of control in the US. It is getting closer and closer to a human-to-human transmission outbreak.

* Measles is resurgent thanks to low vaccination rates.

* Tuberculosis is making a comeback.

* Many norovirus outbreaks.

2/
* COVID rates are lower than in past winters, but a) they're still way too high to ignore, and b) that's because there was a surge in summer (it's not seasonal) and the next major lineage of variants has not arrived yet.

3/
Read 4 tweets
Jan 18
As you read more and more reports of uncommon pathogens infecting a lot of people, or common pathogens surging far more than usual and/or having unusually severe effects, please remember that this is what immunity theft predicts and what we've warned about for years.

1/
By contrast, "immunity debt" or "post-pandemic normalizing of levels" as an explanation makes less and less sense as more time goes by. In 2025, it is absurd to still be talking of new surges of illness being due to the lack of immunity from mitigations that ended years ago.

2/
Case in point, we wrote this more than 2 years ago.



3/calgaryherald.com/opinion/column…
Read 4 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!

Ethereum

0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy

Bitcoin

3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us!

:(