Canada and the Coronavirus

The human mind is not great at dealing with uncertainty. Little is more uncertain than a new variant of a new virus. Will the vaccines work? For how long? Can people be reinfected? Will Covid fade away or become a yearly shot made up of best guesses? We have seen a lot of projections already.

I don’t know the answer to any of these questions. But I do know we will prevail. I know the system will hold. I know we will fight on. We will return to our normal lives in time — hopefully with a deeper regard for connection and enough memories of sacrifice and fragility that promote the persistence of positive changes. Better preparedness. Better long term care. Better people.

That shape is indeed terrifying, if it’s real. Looks like an error to me. Are we really supposed to believe that even under the current lockdown, we can expect the curve to drive to infinity in the space of a couple of weeks? That line is going asymptotic, and leaves the chart at 20,000 cases per day after only a week and a bit? Has any country seen anything like this? The variant in question has been running through other countries.

I’d love to see the source assumptions behind that.

Although I am not an epidemiologist, I see no big reason why the Canadian experience would differ greatly from many similar countries. Canada had the advantage of seeing what happened in places like Italy and Spain first. Though variants could certainly be concerning, and we probably do not know much about those either (including vaccine efficacy, incidence, distribution, infectivity or morbidity). But the very existence of variants is hardly surprising and no reason in itself to change tack. Vaccination was never a panacea. Things will be scary. Things will work out in the end.

With many viruses, variants cause more infections with less morbidity. That may not be such a bad thing. That might be why SARS disappeared without a vaccine coming close to completion. Keep your chin up.

We will fight on with bleaches. We shall fight on with vaccine rounds. We shall fight in the field hospitals and in the sheets. We shall fight coughs and chills. And we shall never surrender…

It’s almost comical. I’m reminded of that “instructional” video from way back on the Simpsons about the dangers of not getting braces.

I’ve only got the actual document and not a Simpson’s reference https://www.canada.ca/content/dam/phac-aspc/documents/services/diseases-maladies/coronavirus-disease-covid-19/epidemiological-economic-research-data/update-covid-19-canada-epidemiology-modelling-20210219-en.pdf

Baseline non-variant model is based on Estimating the impact of COVID-19 control measures using a Bayesian model of physical distancing

Underlying assumption is that the new variants are 50% more communicable. It also looks like the BC/Alberta exposure to a rapid increase in cases due to variants is the main driver behind the large spike in the model where health measures are relaxed.

The problem is, something like “50% more communicable” doesn’t mean much without specifics. What are the super duper new lockdown methods that will apparently work where masks and 6’ don’t?

And since you don’t like the Simpsons reference, maybe you’ll be interested in the fact that Denmark made this same “alarming” announcement about a month ago. Cases continue to plummet there.

More non-Simpsons info:

From Jan 21st. Since then the variant has, in apparently less newsworthy alarmingness, slowed its growth and likely won’t fill stadiums.

The variants could be a problem. But Canada is not an island. Cases are falling, vaccination is coming, and in any case the social distancing measures will need to stay in place. No reason to think the sky is falling.

Well, according to Dr. Tam, if we just keep locking down like we’re doing, very soon 100% of Canadians will be infected, That’s pretty much what that chart shows -that even under the current lockdown regime we are headed for an asymptoic explosion of the virus by March, and the lockdown only buys us a few days before the inflection point hits.

That is, if you believe the government.

@Sam_Stone actually slide 11 has a continued decrease in case volume based on ongoing health measures. Slide 13, where covid variants are introduced to the model sees a jump based on expected health measures.

Here’s hoping Tam’s reading comprehension is better than yours.

@FigNorton I think you’ll find something in page 7 of the medrxiv paper linked, where distancing and infection rates get modeled. Note that the slide in question from the Health Canada presentation (Slide 13 and 17) are heavily dependent on variant presence in provinces with differing mitigation strategies.

There are 2 concerns in my uneducated view. Case spread and % of resulting cases in hospital.

Currently Ontario is ~ R 1.0. Let’s assume Covid Baseline (BL) is actually at 0.9, while Covid Variant, making up, say, 15%, is at 1.6. Overall flat. What happens as the variant begins to be the dominant strain? Change BL/Variant mix to 50/50 and R might move to 1.25.

Consider this BC CDC’s report with differing distancing impacts on spread. http://www.bccdc.ca/Health-Info-Site/Documents/CovidBriefing_20210205.pdf Then consider if contagion moves from the current level to a higher one. (Slide 25)

Now R is only ever measured statically so r = (R-1)/T (T is period) is the growth rate. If we assume the period remains the same for Variant and Baseline then the shift from r= 0 and r= 0.25/T is us losing ground from a case volume perspective. Then it becomes a question of resource consumption.

People seem to indicate that the variant is less debilitating and so would require fewer health care resources to manage when you compare 1 BL case to 1 Variant case. If the growth rate exceeds the reduction, then we wind up in a worse position.

Opening up, while infection rates are high, while new more contagious variants are entering the environment, while contact tracing remains abysmal and vaccination roll out has barely begun would seem to be a choice to put us back into a sever lockdown in short order.

The focus should largely be on ICU capacity and cases requiring hospitalization. Last February, many epidemiologists were asked to guess the number of cases in six months and the answers were all over the map. They still are. We will need to see what happens.

There’s just way too much guesswork on a significant portion of the variables they’re plugging in. I simply don’t trust “~50% more contagious”. When a worst case scenario is so detached from what’s happened in other countries with the variants, it should be discarded and the guesswork reassessed. It shouldn’t be the star of a news conference. Does the Denmark experience I linked not raise an eyebrow when seeing this Canadian forecast?

I mean, guess there’s no point arguing about it. Ontario and Quebec just did a significant reopening. So we’ll see if Canada gets remotely close to 10k cases per day by the end of next week.

"preliminary analysis in the UK suggests that this variant is significantly more transmissible than previously circulating variants, with an estimated potential to increase the reproductive number (R) by 0.4 or greater with an estimated increased transmissibility of up to 70%. "

Paper is from December 2020

Then consider slide 8 in the Public Health deck - hospitalization rates are sitting roughly were they were in early November. Not the summer lull but November as we rolled into the 2nd wave. Now consider a third wave rolling through with that as the starting point.

Regardless, we’ll see.

I don’t see a second wave in November. The last rise in cases started around Christmas.

I posted this in one of the threads about the variants. It colors my perception of how dangerous the new variants are being portrayed:

Doesn’t that article state that by June of 2020 the D614G mutation was the dominant one and so that’s the one we’ve been suffering through? It doesn’t sound like a review of the mutation around the current variants.

Well, yes. That’s the point. There wasn’t an actual increase in how infectious covid was in June 2020 despite that variant’s meteoric rise to dominance. Is there any reason to think the UK variant is more infectious other than its rise in dominance?