Ontario outbreaks by source. Schools (mostly elementary) exceeded even workplaces in terms of outbreak numbers in the 3rd wave. LTC and hospitals are also on this graph. Outbreak timing is by onset date for first case; daily numbers averaged by week for smoothing.
The impact of schools (we didn't change much else) on the third wave has been striking. Workplace outbreaks continued to rise transiently after schools closed, but then fell as case counts fell.
An important additional point: we had literally over 1000 outbreaks in schools, with marked skew in size (range from a single case designated “outbreak” to (rarely) dozens of cases. But there were < 10 hospitalizations from school outbreaks.
Again, the importance of schools is their role as an amplifier of disease transmission that feeds critical illness and death in other populations.

If, 15 months in, you don’t understand that communicable diseases are communicable, I really cannot help you.

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More from @DFisman

9 Jun
@skitsandhersh @jasmith_yorku @Sflecce @DrFullertonMPP @fordnation We can’t time travel backwards. We have to play this forward. If people want a different government we get to choose one next summer. But for now, I feel a great sense of relief that the Premier is getting good information (not from me, but from someone) and making good decisions
@skitsandhersh @jasmith_yorku @Sflecce @DrFullertonMPP @fordnation Ontario is going to have an increasingly prosperous summer. I look around my neighborhood at the battered businesses (watched a guy pass a debit card reader to a customer on a canoe paddle yesterday) and I can see that we are heading for some very good times in the months ahead
@skitsandhersh @jasmith_yorku @Sflecce @DrFullertonMPP @fordnation A real rebirth of our province and our economy, and that’s going to be thanks to high rates of vaccine uptake. We are very very lucky.

There are still choppy waters and hard decisions ahead, but immune experience is the doorway out of the pandemic
Read 4 tweets
4 Jun
A brief twitter thread (1/N) on a really concerning epi paper that's being trotted out as evidence that healthcare workers are somehow at LESS risk of sars-2 infection than the population as a whole.
But first, let's set the stage with some appropriate theme music. This is a bit mean, but frankly, this paper has earned it.

So here's the preprint: medrxiv.org/content/10.110…
It's being paraded around as evidence of the amazing effectiveness of droplet/contact precautions in preventing infection in healthcare workers.
Read 36 tweets
1 Jun
Ontario continues to be a good news/bad news story. The multiwave IDEA model fit from April 27 continues to work well (red circles with 699 for today). The R for presumed "delta" variant (B.1.617) is now at 1, B117 and friends at 0.74. h/t @AshTuite
So we have a ratio of around 1.4 for B1617/B117 (mostly). That's the same dynamic as we had in Feb...if we allow B117 R up to 0.9, that gives us R of 1.26 for B1617. That is literally identical to the math we did in February.
Parenthetically, there are some excellent colleagues in Ontario who have done the same analysis independently and have come to the same conclusions. I'll leave it to them to decide whether they want to share. They may not be able to.
Read 6 tweets
27 May
The Premier’s letter is spot on in terms of the dilemma we face, and the facts at issue. It is a very impressive articulation of the issues at hand and remarkably clear eyed and straightforward. Yes, let’s have everyone put their cards on the table and articulate where they stand
I suspect the Premier didn’t write this solo. Kudos to those who assisted. Seeing a factual, non-political framing like this is very refreshing.

I wasn’t asked for my input, nor should I have been. But my opinion is that the unknown nature of the b1617 threat right now...
...is determinative. We should not roll the dice on 3 weeks of school right now, and risk catastrophe.

We should focus on vaccination, making schools as safe as we can for September, and figuring out other ways to ease the burden on kids right now with safe outdoor activities
Read 4 tweets
23 May
I appreciate this editorial in the Star; I think everyone is anxious for a return to normalcy for kids. That said, there is a repeated emphasis on the toll this pandemic is taking on child mental health in Ontario. Could someone actually share the data that is being referenced?
Data I've seen are a real mixed bag. In particular, critical care admissions for self harm in kids (an index of suicidality) fell like a rock this year. I think assertions like this do need to be backed up by data, which do exist and should be straightforward to present.
Read 5 tweets
18 May
I get that this is politics, but I sure wish they'd lie less about this stuff. It's so freakin unhelpful.
Look: we're in a good place right now though it doesn't feel that way. We are a lucky country that is increasingly vaccinated with incredibly good vaccines, and we are next door neighbors with a country that is also increasingly vaccinated.
I don't think Canada is going to have a fourth pandemic wave, though that's obviously a dangerous thing to write. I do think sars-2 remains a nasty pathogen, and the pandemic isn't going to abruptly disappear...we will need to deal with this for a while.
Read 9 tweets

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