Some very simple models of covid case trajectories in Toronto based on decomposition of old variants and novel variants (b117 right now).
The dashed lines are forward projections. Solid lines are best guesstimates of fraction old (ov) and new (nv) variants based on lab data.
R for b117 seems around 40% higher than old variants, and that ratio was stable through January. So you can run this model forward assuming that ratio remains constant, and assigning an R to old variants (with nv 40% higher).
Our estimate for R right now in Ontario is 0.8. Similar inside and outside Toronto. You can see (top left) that we’d have to be a bit better than this (ov R 0.7) for novel variants not to take off.
At our current level of control (stay at home order, closed schools) the novel variants do increase, but the take off is slow. If old variant R increases to 0.9, that corresponds to a new variant R of 1.26, and we should see a fairly brisk spring wave.
Bottom right is the original logistic curve based on decomposition of some lab data (blue), as well as curves from these simple models. Under any of these scenarios we do see novel variants predominating over the next 4-6 weeks (as they have elsewhere; we are not different).
Tldr here:

1. Novel variants aren’t the apocalypse, but they give us less margin for error, especially as ICUs are already pretty full.

2. Public reporting of NV and OV fractions (even just % SGTF over time) would be really helpful. We can decompose these epidemic curves
I think that will be helpful to decision makers, as these really are distinct processes with different trajectories.

/End
Coi statement: I didn’t watch the Super Bowl, but if you’re talking greatest athlete of all time and not mentioning Serena williams, you need to broaden your interests.

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More from @DFisman

9 Feb
Having been recently encouraged to "stick to the science", I'd like to write a bit about COVID-19 disinformation, where it comes from, and how it is undermining our public health response.
Disinformation is a form of misinformation. The latter is incorrect information; the former is incorrect information that is propagated with intent to deceive and manipulate. The word is an anglicization of the Russian "dezinformatsiya", which I believe was coined by the KGB
Clear, accurate information is critical to our pandemic response; let's go now to my favorite paper on rank ordering of effectiveness of non-pharmaceutical disease control interventions. nature.com/articles/s4156…
Read 29 tweets
5 Feb
So the identity of the @originandclever twitter account (now deleted) has been positively identified. It belongs to a junior physician in central Ontario. I am not going to doxx them on twitter.
But I would like to take a bit of a walk down memory lane in terms of some recent nastiness from this recently graduated physician, writing under the cover of presumed anonymity.
I don't know if this needs to be looked at by @CPSO, @UofTFamilyMed, @McMasterU, @UHN or other organizations this person has been affiliated with in recent years...would love to hear what others think. If journalists want more info, my DMs are open.
Read 25 tweets
5 Feb
I keep getting asked about the possibility that sars-cov2 will be with us for a long time (many of the questions are driven, I think, by Chris Murray’s statement that we won’t simply “put this behind us”). I do think it is likely to become a seasonal, endemic virus
At least for a long time to come. That’s because (a) the virus has show an ability to move from humans to animals and back again (mink) and (b) eradication is hard, even with good vaccines and disease w/o animal reservoirs (polio, measles).
And yet I’m optimistic about a non-reckless return to normalcy over the medium turn. Why?

en.m.wikipedia.org/wiki/You_Are_O…
Read 24 tweets
3 Feb
This is right on.
There is substantial excess mortality right down to age 15.
Absolute death numbers are smaller because baseline deaths are lower
Here’s the most recent estimate I’m aware of.

eurosurveillance.org/content/10.280…

We need to know what fraction of excess mortality in young adults is opioids.
In older adults in the US covid mortality and excess mortality are essentially 1:1

This is a fantastic paper from @AnnalsofIM that reminds us to standardize populations so we make fair comparisons.

acpjournals.org/doi/10.7326/M2…
Read 4 tweets
2 Feb
@DonaldWelsh16 Oh hello.

I knew Dr Rorabeck. He was a wonderful guy. @SchulichMedDent does have much to be proud of. Like any institution, it has its warts.
@DonaldWelsh16 @SchulichMedDent But to respond to your comment: I think you’re referencing the concept of balanced pathogenicity, which probably will will, over the longer term, favour less virulent strains.
@DonaldWelsh16 @SchulichMedDent The difficulty we have with VOC is that they appear to bind better to ace2 (as a vascular biologist I bet you’ve heard of that!) and that may underlie their increased infectivity and increased
Read 9 tweets
2 Feb
The blizzard of distraction coming out of @fordnation and his assorted flying monkeys is by design. It’s a comms strategy. They need to distract you from:

1. Botched vaccine rollout
2. Massive death toll in long term care
3. Muddled and confused back to school plan
4. Political interference with hospitals and health advocates
5. The Mysterious Case of the Missing Rapid Tests
6. Unspent billions in federal pandemic funds
7. Huge excess risk of covid in those with low income and people of colour in Ontario
8. Failure to institute basic measures like paid sick leave
9. Utter lack of transparency on public health decision making
10. Full ICUs, need for field hospitals and transferring patients 100s of km for care
Read 5 tweets

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