A word on the idiocy known as "immunity debt". How did such a nonsensical idea take hold?
Simple. The obvious mental model for our immune system is a muscle: use it or lose it. Muscles atrophy when we don't use them. The same mental model works for our memories & skills.
1/19
So it shouldn't be surprising that a satisfying narrative emerges, using this same mental model, while simultaneously vilifying lock-downs and masks, which nobody liked anyway.
But here's the thing. The immune system isn't anything like a muscle. It's a photo collection.
2/19
Photo collections don't fade just because we don't look at them. They sit until they're needed.
Our immune system uses its "photo collection" to recognize pathogens we have encountered before.
And new mugshots get made whenever a new intruder is identified.
3/19
Eventually as we age, those photos do get wrinkly, like the rest of our bodies, and don't work as well. But they don't fade in kids.
So what's happening with child hospitalizations for non-COVID illness?
Well, pretend you're a virus, and let's call you ... COVID ...
4/19
Your job is to invade, infect, and transmit. Vaccination has made your job harder because your intended victims already have your photo and their immune response is ready.
So you mutate to change your appearance. The more you mutate, the less you look like your mugshot.
5/19
But that's not the only possible strategy: you can also trash the photo collection itself, so your intended victims won't recognize you.
In 2015, it was discovered that Measles does this. It literally erases immune memory. It fades those photos. How was that discovered?
6/19
It was discovered through epidemiological data: people who recovered from Measles tended to THEN get all kinds of diseases they shouldn't get. Nobody suspected Measles was erasing immunity, until we had these data that couldn't be explained away.
7/19
What do we have today? A ton of unexplained child illness in the first cold/flu season since we let COVID rip. Hmm.
We have known since 2020 that COVID harms interferon production, a protein that your cells release to call the immune system for help when they are attacked.
8/19
We have also known for quite some time that when COVID explodes one of your cells, it can trick your immune system into attacking debris that belongs to you, rather than it. That's autoimmune disease.
9/19
In some people, that triggers a LOT of inflammation, which then causes immune system exhaustion. What happens when your immune system gets exhausted from attacking your own body? You stop producing enough T-cells and antibodies to deal with COVID.
10/19
Emerging immunological research is beyond my pay grade, frankly. I struggle to parse these studies for meaning, and immunologists are very conservative about drawing clinical conclusions from their work.
11/19
But I feel certain we will continue to learn the mechanisms by which COVID hobbles the immune system.
It will take some time, this is incredibly complicated science. Maybe a few years. I just don't think we should continue to deny this until then.
12/19
So let's circle back to the sudden rise in child hospitalizations for non-COVID illness. This can't be explained by "immunity debt" nor the tooth fairy, because neither exist.
But it **CAN** be explained by immunity robbery, which we know DOES exist.
13/19
It's true that a couple of years of masking and social distancing means that there is a larger number of infants and toddlers getting RSV and flu for the first time, and it can hit them hard.
If that's all this is, it will soon settle down and the crisis will disappear.
14/19
It will settle down because those infections are happening right now en masse.
However, if COVID is causing immunity harm, and COVID continues to reinfect, then we will see a steady state, or an increase in severely ill children.
15/19
I'd be thrilled to have this all wrong, tbh. Because if I'm right, we may soon start to see child deaths that would be preventable if we had the healthcare capacity to treat them. That's horrible beyond words.
16/19
Now comes the unpleasant part of the thread. COVID is evolving to be more successful in evading our immune responses because we aren't masking or improving indoor air quality.
17/19
That evolution has caused weakening vaccine effectiveness, weakening drug treatment effectiveness, and it may well also include an improvement in COVID's immune suppression capacity. Darwin would say that's almost certainly what is happening, and I'm betting on Darwin.
18/19
People are literally training COVID if they share indoor air without a mask while ignoring child hospitalization, and using "immunity debt" as strong justification for both.
COVID trainers are a majority of the people with whom I interact. I sure wish that would change.
19/19
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I have been inadvertently quiet here for months. A few reasons for that, some fun, some not.
But I'm now 3 weeks into my sabbatical, clearing room for more thinking time.
This includes reflecting on what I'm actually trying to accomplish in the late pandemic era.
1/5
Having been a public epidemiologist since 2020, I think I can boil it down to a need to analyze and talk about things that need to be said, but that aren't being said.
In the first three years, that totaled nearly than 3,000 interviews with journalists.
Yes, I counted.
2/5
But over the last 1-2 years, there has seemed less that needed saying that isn't already being said on this platform and elsewhere by very capable people. That is awesome.
(Although I do wish the media were more engaged in issues like air quality and safe public spaces.)
3/5
This brief thread is very specifically for journalists: some follow me & maybe still drop in?
We need to talk about how COVID burden/outcome measures are reported.
Counting hospital admissions & deaths WAS appropriate in 2020-21.
Now those stats badly misinform. Why?
1/6
Until Omicron, our frame was a respiratory virus that infected & killed rapidly.
Low population immunity and limited understanding of what the virus does to the body, meant that incidence rate, ICU capacity, and deaths told us when things were better or worse.
Not now.
2/6
B/c COVID is a whole-body disease w/ vascular, neurological, immune, & endocrine harms.
Less *acute respiratory* harm now, b/c:
a. the most vulnerable already died
b. we have some population immunity
c. Omicron is less severe than Delta
A cathartic thread about the perils of doing public science communication during a pandemic.
Yesterday, I was notified that I have been granted the teaching stream equivalent of tenure at the University of Toronto where I teach.
This is on my list of major life events.
1/10
I'm thrilled, of course. But this thread isn't about that, it's about the danger of being blunt while precarious, and being unable to properly defend myself.
COVID did *not* make promotion easier. (It did influence my pedagogy narrative, and delayed my review by a year.)
2/10
I accrued a lot of hateful complaints to both my Deans. Sometimes because I was impolite, or because I was right, or because of a fight.
It also needs to be said that my colleagues who are women or/and people of colour get hate much MUCH worse. But still.
Why there is no uniform case definition for Long COVID.
Why we use a variable symptom laundry list, many of which are non-specific.
The second part of this thread considers the negative consequences of this knowledge deficit.
2/19
With a defined disease, we know four things: cause, mechanism, progression, and symptoms. We use these to craft a case definition, which is the yardstick used to diagnose new cases.
With Long COVID, we actually don't know any of these. Let's start with cause ...
An expansive musing thread on mask non-use, which I am now calling "mask akinesia".
Every class I teach, I walk in with my mask and my Aranet4 CO2 detector, to measure air quality. I'm lucky: the rooms I teach in are always below 800ppm and often below 700ppm.
1/20
I make a show of measuring air quality with my mask on.
I often remind them that the air is excellent but that doesn't lower the risk from people sitting immediately around them.
~4% of my students wear masks. ~30% have missed class because of COVID, some cough in class.
2/20
One day, CO2 was 1800ppm, too high! Two of 3 air exchangers weren't operating. I told the class that the air wasn't safe, and to put on a mask if they had one.
They heard me and looked concerned. And nobody moved.