Today we got 4 days of COVID data plus corrections for a couple days before that. The recent increase in cases is now well established, with a recent flattening in the increase. Will that reverse and continue to increase, or go back to decreasing trend? We shall see.
The big question is what caused this? A super spreader event (triva night?) after which we will see declines again? Variants of concern? Probably too early for such a sharp rise, we would expect to see a rise like this this later this month, not now.
Fraser and Vancouver Coastal are driving the recent trend, Interior has come down nicely and Northern also seems to wiggle their way down. Island is still on their path of slow increases.
Individual health regions show more volatility, Fraser is increasing quite uniformly, Vancouver is leading the rise in VCH. Island continue to see low rates in the South, with other regions showing higher rates.
Age groups show increases throughout, with a large recent jump in the 90+ age group. That age groups is quite small, so more volatile but this is not good.
Across Canada it appears that NL got their outbreak under control. Which is truly amazing, although we should wait for another week before declaring this over. BC and SK have traded places again, their switching was a very short-term trend that got washed out. MB declining again!
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Lots of discussions on changing the vaccine dose scheduling in BC. I don’t know much about this, so I asked a friend who are directly involved in research and development of (COVID) vaccines. My takeaway:
1. Vaccine trials have a short first/second does schedule, mostly because it accelerates trials and has lower attrition. 2. When asked, vaccine manufacturers will always point to schedule from trails as recommended protocol for liability reasons.
3. We don’t have direct evidence that stretching the time between doses to 4 months is equally effective (after second dose). 4. We have some evidence that first dose already grants a high level of immunity, at least short term.
TL;DR: Trend lines are an important tool to filter noise from signal. Moving averages is one way to do this, but it's not good at removing noise and introduces a data lag. Using methods like STL that can account for the weekly pattern and don't add extra data lag are preferable.
Moving average trend lines do have the advantage that they are simple to understand, but get misleading when they are artificially shifted to the right to obscure the data lag. This problem is particularly acute when overlaid over case counts as for example in this graph.
In BC we don't have useful geographic COVID breakdowns to e.g. guide schools protocols or direct targeted extra resources. But we can (somewhat perversely) turn this around and use kids as an indicator for community spread.
However, this map is not normalized by (children) population, so here is the children density for reference. Part of the Surrey hotspot in Newton is explained by children density, but there is more than just that going on there.
And children don't necessarily go to school close to where they live, but most do. A better way to do this would be to normalize each school by their overall enrolment, but matching exposures to enrolment data using names is messy and takes a lot of time and I am lazy.
The new Health Region level maps are up, and 10yo did a quick scrape of the data. It's for the week ending this past Thursday. Trends have gotten worse for that past week, although there is slight a caveat (at the end of this thread).
Version with regions stable so people can better follow their favourite health region.
And the map version, things are getting very red across Metro Vancouver. Just to pre-empt the usual comments, I won't adjust the colour scale, it's the case numbers that are too night not the colours that are wrong.
Looks like the data backlog is cleared and we got a full week of new data! And revised data for a bit longer changing the earlier trend that we saw. Trend is again showing signs of slowing growth, but we have been here before...
Vancouver Coastal is showing a decline. Fraser exhibits signs of slowing growth, but also has very high volatility in the numbers. Each of Island, Interior and Northern are showing higher growth rates than the VCH and FH, which is also evident in their combined trend.
Of course these tweets might be obsolete again in half an hour if BCCDC again pulls the update as happened last week and also the week before that. ¯\_(ツ)_/¯
This is really quite something, although not unexpected given what we have seen. BCCDC would really benefit from adopting a privacy framework instead of just relying on as-hoc decisions.
It’s really hard to rationalize why publishing weekly counts for Richmond is just fine by doing the same for Burnaby or Surrey would be an “unreasonable invasion of privacy”.
In fact it’s really hard to rationalize disclosure risk at much finer geographies like FSA or City Neighbourhood, when we already identify the existence of cases in school communities.