I haven’t written about Covid-19 for awhile

I haven’t written about it much recently because I didn’t have much to say that added to the discussion. In Australia things are opening up again: most schools are open (but not ‘back to normal’), restaurants/cafes have started limited seating and generally people are out and about in shops and offices more. The running total number of cases are low (7 thousand) as are the total number of deaths (102). Luck and timing seem to have made a huge difference here but the big question is how big that reservoir of unobserved infections is. With more wintery weather here and social contact increasing, we’ll need to see if the infection rate starts zipping up again.

Meanwhile, nonsense continues from the usual suspects elsewhere. I’ve seen more than one attempt in conservative and global warming denial circles (but I repeat myself) trying to do a comparison of lockdown policies with infection rates and/or changes in infection rates. The idea is to roughly classify a nation’s response and then look at levels of infection and then (lo and behold) find no connection and declare that lockdowns did nothing.

The reasoning is fallacious. The fallacy is one we’ve seen before: looking at data but stripping out what we already know. Lockdown policies are connected to infection rates in multiple ways. Consider two different examples: Italy and New Zealand.

Italy suffered a massive early spike in infection rates relatively early for a European nation. With hospitals overwhelmed in the north, the country began quarantine measures at a point were relatively little was known and access to testing was limited. As a policy response it was pretty much an extreme emergency measure where authorities had very few options available to them. On the other hand (and in real time, not very long after) New Zealand adopted a strong lockdown policy precisely because the country had very FEW cases. NZ had a shot at an elimination strategy: close off people entering the country, shut down community spread, wait for a few weeks…and (maybe) the virus is gone.

So we have a range of policy measures that have been implemented as a response to quite different circumstances. Among the countries compared, most have significant measures in place of some kind but there is a lot of variety on specific ones (e.g. school closures is quite varied as a policy) and the impact of a government ‘recommending’ as a measure and enforcing a measure is also varied (i.e. in one nation a recommendation might have had a similar practical impact as a mandated policy).

In short, it’s a mess that will require more complex analysis than simply comparing ‘lockdown’ v ‘no lockdown’. The Our World In Data site has a decent overview of policy responses here https://ourworldindata.org/policy-responses-covid They also have a kind of aggregate index for a variety of countries (https://ourworldindata.org/policy-responses-covid#government-stringency-index ). How useful that is, I’m not sure. Again, simply comparing one date with total infections will produce gibberish e.g. currently NZ has a less severe score than Sweden but that hides that NZ had a VERY severe score ten days earlier, so you have not just different levels of severity but different PATTERNS of severity.

What happens next? Different regions have been impacted at different times. Obviously East Asian nations suffered the initial spike, followed by Western Europe and then North America. Cases continue to grow in the USA, although that growth is partly masked by falls in the parts of the US that were impacted first.

This graph shows some selected nations based on previous conversations or places that people have made comparisons between. Different choices of countries might lead to a very different perception of the trajectory. Also, as we’ve discussed before, the extent and efficacy of testing impacts these numbers.

Russia, parts of South America and the Gulf States also have rising numbers. The worldwide spread is far from over.

16 thoughts on “I haven’t written about Covid-19 for awhile

  1. Waiting for the second wave rolling in. I don’t think the economy will be able to outlast that one.
    Low numbers don’t help as long as there is no vaccine available.

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      1. I think that’s the idea of trying to get the numbers very low now – it frees up resources for testing and contact tracing to keep the lid on future outbreaks. If you have good testing and tracing then new outbreaks mean you just quarantine the people involved, not everyone in the region. And your medical staff are not exhausted either.

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  2. We’ve taken the New Zealand approach here in South Australia. We were the first state to close our internal borders as well as international ones, and we did it when almost all our cases were coming from either interstate or elsewhere. As a consequence we have had less than 500 cases and 4 deaths in a population of ~ 1.4 million (85% of which is urban).

    I have been pleasantly surprised at the way our government has responded to this, but our population is skewed very elderly and I wonder if the Premier has seen some horrifying projections about the outcomes if the virus got loose here.

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  3. To make the graphs more meaningful, I compute the new cases (I just subtract yesterday’s cumulative number from today’s) and then I compute the 7-day moving average of that. This produces a relatively smooth curve that nicely cancels out most of the day-of-the-week effects. That’s critical for interpreting the Italian data.

    Another trick that’s very sensitive to changes is to take the natural log of the ratio of the new cases for this week divided by the number for the previous week. Plotted over time, this makes it really clear when things like lockdowns started making a difference and when they’ve lost effectiveness. It’s easily messed up by places that keep updating their older numbers though.

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  4. I don’t care at all about comparisons of numbers of cases in different countries as they are dependent on the number of tests performed and where those tests were performed.

    As an example, Sweden found 3711 positive cases in week 15 and 3728 in week 18, almost the same on paper. But 19 880 tests were performed with 19% positive in week 15 and 28 997 tests in week 18 with 13% positive.

    And even that isn’t the truth as the increased testing capacity has caused a change in who are tested. From only testing those who showed symptoms ans were sick enough to need a hospital stay, we now test wider among employees in homes for the elderly and in hospitals. So the real decline is somewhat smaller.

    And if we instead go by larger surveys, tests among the personnel in our largest hospital showed that at least 15% of the personnel had been infected, not including those on sick leave. There was no difference between personnel working with Covid19 patients and those working in administration somewhere else. An antibody test on those seeking help at clinics for various ailments showed that 7.5% of the population were infected in week 15.

    So I don’t really see that those graphs with comparisons between countries show much of interest as I don’t know the background of the testing. Better to compare use of hospital beds.

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  5. The link to the policy responses is also wrong for Sweden:

    * It says we “recommend school closures”, but in fact we require distanced schooling for senior high school and universities.

    * It says we have no measures against public events. In fact, all commercial events of more than 50 persons are illegal, including all sport events, festivals, concerts and more.

    * It says we have no stay-at-home restrictions, but we are recommended to work from home and to not do unnecessary travel.

    * It shows no measures for public transport, but we have large posters saying we should avoid travel by them and constant warnings in speakers to socially distance while travelling.

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    1. There’s a lot of misinformation regarding the measures and approaches in different countries floating around. Sweden gets hit particularly hard, because everybody wants to use your country to make a political point, usually without having a clue.

      Also, I’m very sorry about Karl Lauterbach, loudmouth politican without an office who seems to permanently live in political talkshows now and tweets almost as much as Donald Trump, who said mean and wrong things about Sweden last week. Believe me, lots of Germans can’t stand Lauterbach either.

      I also got into a discussion on Twitter today with some Americans who used a video of a protest in Germany against vaguely worded anti.-corona measures. In a supermarket in Mecklenburg-Vorpommern, four women took off their underpants and pulled them over their head, when asked to cover their mouth and nose, because according to the local regulations, wearing underpants over your face is sufficient to fulfil the requirements, even though it doesn’t protect anybody. These women were very careful to maintain the required two metres distance, they were not aggressive and made sure to stage their protest at a time when the supermarket was nearly empty. Besides, the protest happened three weeks ago.

      However, some Twitter user decided to tweet the video as an example of entitled Trump-voting “Karens” endangering innocent supermarket employees. And when I pointed out the actual background of the protest and that the video wasn’t even taken in the US and that maybe they should check the source before posting something, the reaction was not exactly friendly. One person even claimed that this protest was obviously connected to the idiots parading around with their guns in Michigan, because of a global conspiracy of QAnon adherents. So it’s not just the right who are susceptible to conspiracy theories.

      Also, a lot of Americans are unduly freaked out by the sight of women’s underwear.

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      1. Mr. LT went out wearing a gym sock mask recently. But it also has a filter pocket and I have a box of coffee filters. Also, he was 6 feet away from exactly one other person in the store (who was also masked, city law) the entire time. I don’t think he’d wear his own underwear even to make a point. He’s shy.

        I found an old t-shirt that’s too small for either of us, so we’re going to move up to making masks out of that. We’re restricted to no-sew ideas. I have some surgical-type masks, but I’m trying to stretch those out as long as possible — reserved for going to the supermarket, pharmacy, and so on.

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  6. Well, and the other thing is that lockdown measures are to keep the number of cases down and keep the hospital system from being overwhelmed. It’s like saying y2k was a big hoax because nothing happened, when the reason nothing happened was because of the thousands and thousands of man hours programmers put in ahead of time to make sure nothing would happen. We don’t know what would have happened if we hadn’t put the lockdowns in place, but obviously, since the bad things didn’t happen and the hospitals weren’t overwhelmed, then the virus can’t be that bad.

    *beats head against wall*

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    1. It was the same thing with the Y2K crisis… there would have been significant issues if it hadn’t been dealt with (mostly in banking and payroll systems) but because it took a widespread panic to actually get people to act, and then after they acted nothing obvious happened, people started complaining about the ‘hoax’.

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