Covid: Trajectory

A few weeks in and Australia is still struggling to get on top of the recent delta-variant outbreak of covid. It’s apparent that the initially muddled and delayed lockdown in Sydney was too late to keep the virus bottled up and it is now spreading in more rural areas.

As regular readers will know, I’ve tried to stick with one fairly consistent way of looking at covid numbers: cumulative confirmed cases per population size. There are no perfect numbers and these figures have the same issues in terms of being dependent on testing rates. However, my point about the graphs has been that it is not so much the magnitude as the slope of the graph. Lower testing rates may obscure or delay how that graph gets steeper but when the virus is spreading exponentially it will show up in the numbers.

On the “delay” aspect with testing, I thought I’d illustrate that with a simplified graph. The underlying data is a number that increases proportionally by 1.2 times the previous “day’s” number. Two lines show 5% of the current day’s total (blue) and 1% of the current day’s total. Obviously, testing rates do impact the number of reported cases but inevitably the numbers go wooosh regardless.

Putting the curves side-by-side helps show how the pattern is similar but these two lines look identical if plotted with different scales on the vertical axis. The underlying shapes are similar in a mathematical sense where the difference is scale.

Anyway, still locked down for the time being and the curve is still going up.

21 thoughts on “Covid: Trajectory

  1. We have low casenumbers but they are rising quite a bit. I am happy to have gotten my second shot 2 days ago and onl need to stay safe for less than two weeks now. Getting a shot is at the moment pretty easy here. I heared a radiospot where you could get any shot you want without having to have a date, so progress.
    We also had a newspaperarticle today, that showed a very scary picture of the situation in the USA.

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    1. What scares me about those numbers in the US is the likelihood of another variant version. We can hope that it might be less deadly but either way the odds are is that it will be more easily transmitted.

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    2. I still have to wait until August 18 for my second shot, but there are plenty of free slots with all vaccines available here at the moment, plus the EU just approved the Moderna vaccine for use with 12 to 18 year olds.

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    3. @Cora: My brother is in the same situation, he gets his second shot a few days earlier than you. (Your part of Germany was more succesful in vaccinating his people than mine was, congrats)
      We have now left the part were getting the (first) shot is a matter of luck, but a question of want. I hope a lot of people getting vacinated. (With a few exceptions, I have a cousin, who can’t get vaccinated until October because he had Covid)
      @All: I hope you stay save.

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      1. At least in Germany, the vaccine is no longer scarce, so I hope that those who are not vaccinated yet will get their shots soon. I suspect that vaccination rate will go up again, once the holiday season ends, because right now a lot of people are on vacation.

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  2. Over here in the UK we’ve adopted a policy of “let it rip”. The government has decided that it’s not going to take any political hit from any decision it takes at the moment*, so it’s basically taking the same approach that it took last July and calculating that the vaccine rollout will be sufficient to control things until well into the Autumn (although it is facing the problem that it’s becoming clear that ‘booster shots’ are going to be needed on a regular basis and it may have to start on those before reaching a sufficient first jabs threshold…) It’s entirely possible that Johnson will need to ‘cancel Christmas’ again though, which would be very, very bad.

    *it’s probably correct. Even a public inquiry (which will be delayed forever) is probably only going to put on record things that people who are paying attention already know, and people who aren’t paying attention probably aren’t going to suddenly pay attention to that.

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    1. Hancock is widely agreed to have had a bad pandemic. But with current policy I find myself wondering whether he was the voice of sanity in the Cabinet.

      A few weeks ago Scotland had the highest case rate in Europe. The case rate there has subsequently fallen significantly. The case rate in the UK as a whole has just turned down. I suspect that the latter is due to the closure of the schools for the summer break. It’s too early for this to show up on transmission, but I suspect that they’re not testing schoolchildren regularly now, and this has cut detection of cases. So I wonder if the fall in Scotland was due to the same reason – they closed 3 weeks earlier than England. (I’m not aware of any policy change that would explain the fall in Scottish case rates.)

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  3. Stay safe! New Zealand has put a two month pause on quarantine-free travel between Australia & New Zealand.

    I watched with horrified fascination as New South Wales kept holding off on more stringent responses, lie they weren’t paying attention to what happened to Victoria last year. Or maybe they thought she’ll be right, it won’t happen to us?

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    1. Sadly both state rivalry, partisan politics and the Murdoch press played a role in that. Lockdowns were seen as as being overly hasty and draconian moves by Victoria’s Labor government, so the wise Liberal heads of NSW would people to deal with the pesky virus without such measures.

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      1. Plus, of course, lockdowns are economically dangerous, and we all know the money is more important than actual people. This is added to the fun of there having been no federal support for the lockdowns (because again, economically damaging and we must keep the money flowing) so if you wound up locked down and out of work / hours as a result, your only recourse was Jobkeeper (at the old, $40 per day rate) and performing “mutual obligation” activities such as visiting employment service providers and Centrelink offices. Compound this with the seriously mucked up vaccine roll-out (and the federal government trying to blame the slow rate of the roll-out on vaccine hesitancy, rather than their own lack of competence).

        Meanwhile, over here in Western Australia, where we lock down early, quickly, and relatively often given the size of the population, we seem to be doing a lot better. Why, you’d almost think lockdowns work.

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  4. Not just locked down here but half the household is technically quarantined. Spouse and middle child were at an exposure site last week, albeit a ‘tier 2’ one. It took ten hours in a queue for them to get tested, there’s been such a run on tests here, but they got negative results back this morning, thankfully. They still have to get another next week before they are free to leave the house.

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  5. Even Republicans are starting to utter the truth that dare not speak its name.

    Too little, too late — they did too good a job of keeping their fanbase away from shots. Killing off your own voters is pretty stupid, but then they’ve been “the party of stupid” for quite some time.

    California has gone back to “wear masks indoors, ya dummies”. Not that I’d ever stopped, except for that one restaurant dinner. Looks like drive-thru, delivery, and my own cooking for the foreseeable future.

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