Comment by dmurray | Hacker News Reader

Comment by dmurray | Hacker News Reader

It seems to me that the lesson we should be learning from Sweden is different.

The measures undertaken in Sweden weren't sufficient to control the spread of the coronavirus at the start. They saw exponential growth like anywhere else that did not impose a lockdown. But the growth stopped faster than predicted by any models of herd immunity. They're now seeing 300 new cases a day, compared to 1100 at their peak. They've had about 1% of the population test positive, and about 0.1% of population die - and neither of those numbers look likely to grow significantly. You can quibble over testing statistics or death reporting, but they've had about 50% of the testing rate of Florida [0] and the excess deaths are within a factor of two of reported deaths[1].

If only 20% of people are immune to Covid-19, with a base reproductive rate of well over 1, this slowdown simply couldn't happen. The truth is there's something else going on: either it's way more infectious (but less dangerous) than realised, or more likely, a very large proportion of people have baseline immunity to the infection. It spreads rapidly through those who had no previous immunity and then burns out.

So it's not that Sweden did things right. They chose to be the control case for the lockdown experiment, and they got lucky that the virus isn't as bad as we thought. Back in March, it was a totally reasonable belief that the virus if unchecked will spread to 60-70% of people and kill 1% of those - we'd only seen the spread rates from the early days of the pandemic in China. Now, the only observation we have from leaving the virus unchecked points to a much lower number.

It's still rational for governments to err on the side of caution and wait for more data (especially on long-term effects), and to manage the pandemic to avoid saturating hospital and ICU use. But it's not rational to treat a disease that threatens to kill 0.1% in the same way as one that threatens 1%. If we see similar results in Florida - a region with good data and a reckless/casual approach to lockdown - we should see a peak in terms of new cases/day in the next three weeks and then it will be time to really accept that the risk is lower than we thought.

[0] almost all stats from https://www.worldometers.info/coronavirus/country/sweden/

[1] excess deaths from https://www.euromomo.eu/graphs-and-maps/

> there's something else going on: either it's way more infectious (but less dangerous) than realised, or more likely, a very large proportion of people have baseline immunity to the infection. It spreads rapidly through those who had no previous immunity and then burns out.

I don't think this can be the explanation, because it would not account for how geographically localized it was in Sweden. The Stockholm metro area got hit heavily, but the rest of the country was comparatively spared, and it never became big in southern Sweden. If people had prexisting immunity to coronaviruses you'd expect the immunity to be equally distributed, so it should burn through the entire country.

To me, that sounds more like there was an outbreak that started in Stockholm, but then they added social distancing measures which were enough to slow it down...

> it would not account for how geographically localized it was in Sweden. The Stockholm metro area got hit heavily, but the rest of the country was comparatively spared,

This doesn't match the statistics from here [0] [1].

The case rate in Stockholm county is 9.5 per 1000, making it the fourth hardest hit. 15 of Sweden's 21 counties, accounting for 80% of the population, have rates of 5 per thousand or higher - higher in the urban areas. The deep south of Sweden is the exception, not the rule - despite being home to a large city in Malmö, Skåne and the four surrounding counties have only 3 cases per thousand. I don't have a better explanation for this discrepancy but it's definitely not an outbreak localized to Stockholm.

[0] https://www.statista.com/statistics/526655/sweden-population...

[1] https://www.statista.com/statistics/1103949/number-of-corona...

I think it’s an artifact of how widespread the contagion was when restrictions were implemented. Stockholm has about twice the death rate as Västra Götaland, but lower case incidence. This is all plausibly explained by the observation that the epidemic started in Stockholm, and there were already hundreds of cases there when restrictions were enacted on the 18th of March. Protective gear was in short supply, supply lines were disrupted and the spread spiralled out of control. Other parts of Sweden had a far smaller case incidence at this point, so the restrictions were more effective, and by the time it became widespread in, for instance western sweden, supplies weren’t as scarce, certain lessons had been learned etc.

Some other explanations: The rest of Europe shut down and also shunned Sweden (most still do when it comes to travel from/to Sweden), which effectively put them in a forced isolation whether they wanted to or not.

Same goes for lockdown. While it wasn't mandated as strongly as other countries, lots of people self-imposed those restrictions. So it cannot be compared as lockdown vs no lockdown.

Neither of these offer any explanation to why there would be exponential growth for four months, followed by a flattening of the curve and a sharp decrease.

Being isolated from international travel is helpful when other countries have the virus and you don't, not the other way round. And I haven't seen anything to suggest that people restricted their movements in June/July than the previous months.

You're right that it's not a perfect control group as there was some change in behaviour. But that's not relevant to my argument that we now have a good data point for the total "area under the curve". If they'd had no change in behaviour, we'd have seen the peak somewhat earlier. I don't have a good feel for whether people in Florida are restricting their behaviour more or less than Swedes - seems close enough to consider them the same.

Come on, it was pretty obvious from very early on (during the Wuhan outbreak, then validated in Italy soon after) that the disease did not kill 1%, the symptoms for the vast majority of those that get sick are mild (to even being asymptomatic), moreover that the age skew was extremely strong. The median age of death is over 80!

All these factors together were used to decide on the strategy. Subscribing it to luck is unfair. It is more about expertise or lack thereof. A bureaucrat with little practical expertise is less likely to take risks since they are afraid of being exposed as lacking knowledge. Anders Tegnell most certainly was not afraid of going against the grain.

Introducing lockdowns in nursing homes early on would have avoided probably 60%-80% of deaths. This applies to Sweden and other countries as well.

> Come on, it was pretty obvious from very early on (during the Wuhan outbreak, then validated in Italy soon after) that the disease did not kill 1%

I don't think this was that obvious. Without widespread testing it was hard to tell how many people had got the virus. In China, 1 in 20 people who tested positive have died. In Italy it's a shocking 1 in 7. That's using today's figures: it was even more back then.

I remember respectable bodies estimating 0.5% or 1% mortality rate, though I can't find a WHO source that is more committal than "it appears to be worse than seasonal influenza". I'd call it a calculated risk.

To know the actual mortality rate you would have to test every single person in a country. Right now is more of the cultural thing: How likely is the person experiencing flu-like symptoms to go and test for coronavirus? Seems that in Italy only seriously sick people would go and take test, that's why you have this shocking 1 in 7 rate - because most of the mild cases go undetected.

"[..] that the disease did not kill 1%"

This is new for me. My understanding is that the current total mortality estimation is a little below 1% but, as you say, very skewed to old people.

That is: for old people is a lot more that 1%

Can you share any data that contradict that?

You're ignoring that Sweden implemented mostly the same social distancing measures that everyone else has. That's why their spread slowed down. No official nationwide lockdown does not mean the virus was unchecked. Besides, viral spread is not a direct function of government policy. In all likelihood, Swedish people saw their numbers going off the charts and started taking it more seriously and being more careful in their daily lives.

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