2021-05-22/23/24 BC

It was kind of slow over the weekend, so I’m doing three days at once.

Mitigation Measures

The police cleared out a crowd at English Bay beach on Friday at 10p when the beaches officially closed.

Police turned back about 100 cars and fined two at travel-denying checkpoints. Those two just… didn’t stop.


I have been saying for some time that something magical seems to happen once you reach about 40% of the population vaccinated, that cases sort of go into free fall. I thought we would have fewer cases than we do now. (Spoiler: I was wrong.)

I went back and checked my assumption. Israel did go into a free fall at about the time they hit 40% (Feb. 7), which was in conjunction with some strict measures:

However, if you look at the UK (which hit 40% on 26 March), their big drop was much earlier (starting Jan 9) and was clearly related to restrictions.

Similarly, the US (which hit 40% on 21 April) had its big drop starting around 13 Jan, again, related to measures.

if you zoom in and squint at the 40% points (red lines) for the UK (19 Mar), US (14 April), and Canada (10 May), you can maaaybe imagine that there is a linear drop somewhere in the vicinity of the 40% line. For the UK, it starts a week after the 40% line; for the US, it starts nine days before the 40% line; for Canada the linearity starts at just about exactly the 40% line, but the drop really started earlier.

Now, if you try to do this with BC (which hit 40% on 7 May), the start of the drop corresponds exactly to more stringent mitigation measures, not to vaccinations. Passing 40% does absolutely nothing.

So… I was just flat-out wrong about something magic happening at 40% vaccinated. The magic is in the behaviour restrictions, not in vaccination.

Another thing which I have sadly accepted is that you can’t vaccinate fast enough to get out of this pandemic.

This is perhaps best illustrated by Seychelles, where lifting mitigation measures too soon gave them a really bad outbreak even though 70% of the country was vaccinated. 80% of the people who were hospitalized had not been vaccinated, and that was still enough to overwhelm the hospitals. (The 20% who had been vaccinated were not as sick, in general, even when hospitalized, however, so getting a vaccine is still a good idea.)

This has bothered me. “Why”, I ask myself, “don’t I see case counts falling when the vaccination rate goes up?” I finally realized that until we hit herd immunity, even if we are only slightly below herd immunity, then R, the reproduction number, will be over 1, which means it will still have exponential growth. It will be slower exponential growth than at a higher R value, but the thing about exponential growth is that it will bite you. You can’t run from exponential growth for very long.

For example: eyeballing, it looks like R was about 1.4 right before the most recent wave. 1.4 doesn’t sound all that big, but that wave hurt us badly. Compare this to an R0 of about 3 for COVID Classic and 5 for B.1.1.7 (meaning in an unvaccinated population with no mitigation measures), and you can see why it is important to have mitigation measures. 😞

From the 13 May 2021 Weekly Data Summary

So the depressing news is that we can’t stop doing mitigation measures until we’re at herd immunity levels, which might be as high as 85% with two doses. (Wildcard: children have much reduced infectivity, so it’s sort of like they are vaccinated with a not-very-good vaccine. Alas, I haven’t seen anybody figure what herd immunity you need if you treat the minors as having partial immunity.) The good news is that vaccination reduces R, so you need fewer restrictions to get R under 1.0.

Thus, the thing to do is to keep relatively strong mitigation measures around for a while, to crush the case count, because the case count is what really matters. (You are far, far safer being unvaccinated in New Zealand than vaccinated in India right now.) Then you need to have really strong test/trace/track to nip any outbreaks in the bud.

Sorry if that’s not what you wanted to hear, but blame the virus and not Public Health.


Fri/Sat: +356 cases
Sat/Sun: +325 cases
Sun/Mon: +293 cases

Over the weekend there were +12 deaths, +136,730 first doses, and +4,738 second doses.

Currently 292 individuals in hospital / 96 in ICU, 3,953 active cases, 136,603 recovered.


The dashboard didn’t update today, so I can’t make the supply charts.