Sweden

Update: (27/5) If you compare Sweden with a lockdown imposed on the same date as UK (March 23) then Sweden is apparently doing much better.

Everyone is watching Sweden where the chief epidemiologist Anders Tegnell has resisted lockdown. Cafes, schools and restaurants have all remained open throughout. Their policy of voluntary social distancing measures while protecting the elderly seems to be working.

I ran Ferguson’s model for Sweden after finally working out how he normalises to different populations. Basically he normalises model death predictions to those actually recorded for a specific date. For the UK this date is April 10 (10,000 deaths). This is how the model compares to Sweden if I use the same date (400 deaths). First with lockdown on 23 March.

Swedish deaths are less than predicted under a March23 lockdown scenario

Now with lockdown a week earlier on 16th March

ICL model compared to deaths in Sweden. The blue curve is a UK style lockdown beginning 16th March ( a week earlier than UK). The red curve is unmitigated deaths. The green curve are recorded deaths.

Accumulated deaths then appear to be about 1000 higher than they would have been had they applied a UK style lockdown on the 16th March. However the UK figures also show an overshoot of about 5000 deaths even with the 23rd March lockdown.

Different ICL lockdown timing simulations. The green and cyan graphs follow what actually occurred.

So in general Sweden and the UK are in a similar state currently. However the Swedish trend is showing a smaller decline implying that R is around or slightly above 1. If the goal in Sweden is to reach herd immunity while protecting the elderly, then it seems to be working. Everything will depend on whether a vaccine becomes available in September. If not then Sweden’s strategy could well pay off.

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32 Responses to Sweden

  1. tallbloke says:

    Lockdown. All pain and no gain isn’t it?

  2. Are you interacting with Neil Ferguson about all this, Clive?

  3. Jerry says:

    Of course, Sweden is not the U.K. Culture plays a big part with voluntary social distancing. That is tough to model.

  4. Andrew Carey says:

    @Clive – In your delving have you come across either R varying with seasons, and/or the herd immunity level varying with seasons.
    To me this is important as you could have a summer R of 1.2 with 20% of people already immune, and the disease dies off gradually.
    Dial that R up in winter because we go to more indoor events, and the virus lingers longer, then you could have a late autumn R of 1.8 with 30% of the people already immune and the disease escalates, and will do so in local pockets.
    I just can’t handle life at the moment, but more than that is knowing people who are genuinely scared. They don’t even want to know about risks. If just one case appears in the local primary school they will want a severe lock-down again, parks closed, the lot. Everything I read indicates Sweden has this, but the UK will get surges late this year for the above reasons and some people will get hysterical.

    • Clive Best says:

      I think you’re right that R must vary with season. The epidemic must naturally help suppression in summer. I don’t claim to be an expert. I am just trying to understand Ferguson’s model which had such an impact.

      Yes a lot of people are scared. How are we going to get back to normal?

      The high UK death rate is likely due to the “save the NHS from being overwhelmed” policy of moving elderly patients back into care homes without testing them. Many were already infected in hospital.

      However things are slowly improving.

      Life will get better.

  5. Protecting the elderly? Is that a joke? 4125 deaths so for in Sweden. 3642 from the age group 70 and older.

    Compare Sweden to neighboring Finland, Denmark, Norway.

    https://ourworldindata.org/coronavirus-data-explorer?zoomToSelection=true&time=2020-03-15..&region=Europe&deathsMetric=true&totalFreq=true&perCapita=true&smoothing=7&country=SWE+DNK+FIN+NOR

    Their goal is not herd immunity. Denied by the government and the chief epidemiologist.

    https://www.npr.org/2020/05/25/861923548/stockholm-wont-reach-herd-immunity-in-may-sweden-s-chief-epidemiologist-says

    And as we all know. People keep getting infected after the herd immunity threshold.

    • Clive Best says:

      It is the same in UK. Half the deaths are in the elderly.

      Herd immunity is supposedly reached when R naturally falls below 1. However people still get infected and die until the number of infections fall to zero. So when you hear a quote that herd immunity is reached when 60% of the population have been infected, it actually means that 80% finally get infected of which 0.5% may die.

      • And everywhere. Like Norway. In Norway the elderly have fewer restricting advice/recommendations than Sweden. In Norway: live like others. In Sweden: keep away from others. Stay home. Meet peple in parks etc. That is because the infectious rate is much lower in Norway and there is lower risk for infections.

        Is locking up the elderly the preferred option?

        Btw. Norway did not close cafés, restaurants, retail shops. No curfew. Sweden has now stricter travel recommendations in the country than Norway.

        Sure is a better option to use the total infected than stressing the herd immunity threshold.

        • Clive Best says:

          Yes Norway and Poland have remarkably few cases/deaths. Do you know why? Perhaps they have an effective test, track and trace programme. Poland has done better than Germany !

          • Rune Valaker says:

            In the beginning – in mid-March and beyond – Norway had among the highest test rates in the world and an aggressive follow-up to each new infection. We also had very many cases in relation to the population, much higher than Sweden, Norwegians travels a lot. Now the test rate is lower, there are several test programs of a scientific nature and FHI had plans to let everyone who would be allowed a test, but this they have left as they thought it would be wasting resources. According to their calculations, one would on average had to take 16,000 tests to find one positive. But if You insist You will get a test, I did before I visited my old mother for Easter, just as a precaution.

  6. Jerry says:

    And 4K if you go down to 60 years old. Not much protection. Are older lives worth less? What if this virus had the death profile of the 1918 epidemic? 15-44 year olds would be singing a different tune. Lives matter in any model. No matter the age.

  7. JerryJames says:

    And any flattening of the curve buys time to develop more robust treatment protocols which could reduce hospitalizations and invasive therapies such as ventilators. Which in turn reduces death rates.

  8. Nathan says:

    I think you need to investigate what Herd Immunity is:
    “Herd immunity is supposedly reached when R naturally falls below 1.”
    You’re basing your ‘public policy’ on reaching Herd Immunity, so you better know what it is.
    Would also be good to know if Humans have ever achieved it without a vaccine. Can you give some examples?

    • Clive Best says:

      The 1918 flu pandemic ended with “herd immunity”. Over 20 million people died worldwide beforehand. Supposedly herd immunity is when the disease runs out of susceptible people to infect. R0 reduces because there are less and less people left who are susceptible. I have no public policy.

      • Nathan says:

        Well deliberately seeking our herd immunity seems like a poor strategy, especially if the IFR for this disease is higher (and recall we had no information about it; we only knew about SARS which was very lethal).

        It also seems like a poor strategy if we don’t even know if we can get herd immunity. It’s a terrible assumption to make.

  9. Rune Valaker says:

    In mid-March Norway and Sweden had about the same number of cases and similar developments. Sweden has about twice the population of Norway, about the same health care system etc. Now Norway has a few deaths a week, and 10 – 15 new cases of infection each day. At present, 36 people are admitted to hospitals, 10 of whom are on intensive care. In Sweden, the numbers are 1600 and 600 respectively and the health care system is very much under pressure. They have hundreds of new infections every day and one of the highest death rates in the world in relation to the population. Sweden is not close to herd immunity, less than 8% of the population has been infected. This cannot continue for months, something that Yesterday prompted Sweden’s biggest newspaper, Expressen, to request a changed strategy. On March 12, Norway, Denmark and Finland chose to partially lockdown, this has gradually been eased and life is about to be normalized. Spain, Turkey etc. have invited Finns, Danes and Norwegians on summer holidays, but not Swedes. And both Finland, Denmark and Norway will maintain travel restrictions to and from Sweden. Herd immunity is a bad strategy to fight Covid – 19.

    • Andrew Carey says:

      This cannot continue for months I beg to differ, and have got Chris Whitty on my side on this. Some combination of people getting ill and/or being restricted in our freedoms is going to go on for a very long time. There might be short periods of up to three months where there is no lockdown and very few infections, but it is a pandemic – every local authority area in every country with an international airport has had it. And the best mitigation by far is to wash your hands in still soapy water every time you enter or leave a building with the facilities to do so. (Taiwan centre for disease control effectively says this).

      • Rune Valaker says:

        I think we agree, what cannot continue for months is that Sweden has the highest number of deaths pr. capita, 6 – 700 new cases a day without any possibility to trace and isolate them, and a healthcare system on the brink of collapse. What You are describing is exactly what we do in Norway and we are prepared to do it for as long as necessary. The Swedes must press down the spread of the virus, Their strategy has been very unclear and changing, flattening out the curve is no strategy if the current state is to continue for months and years, it will take at least a year to achieve herd immunity.

        • Börje Månsson says:

          There are three ways to end the virus spreading in a country:
          1. Eradication: No more are contagious but there is no herd immunity. As soon as you open up your borders you are risking another wave because you are importing infected people.
          2. Herd immunity: d/dt(I)<0 for good . You can open up completely without risking another wave even if you are importing a rather large amount of infected people.
          3. Vaccination.

          The third alternative is of cause the best.
          Alternative 1 seems to be working fine in the beginning but you are risking having more than 2 waves.
          Alternative 2 is in practice impossible to reach in one wave unless you have gigantic health care system but it is possible in 2 waves. The number of dead people per capita and day will be higher than for alternative 1.
          The total number of dead people per capita will in practice be the same for all strategies which have any sort of restrictions.
          It is only a matter of how many waves you distribute your dead people over.
          If you are planning to keep your restrictions forever or you can have vaccine before wave 3, alternative 1 will end up with less dead people.

          To compare different countries to see which has the best strategy is rather meaningless, because
          Every country has specific initial conditions (Different initial number of infected people, different R0, different CV-number (Coefficient of variation)).These initial conditions have huge influence on the development of the spreading.

          • Clive Best says:

            I agree with you. If we want the world to return to normal to avoid an economic collapse, we either need a vaccine or herd immunity ( like 1918). We should however be able to reduce the fatality rate with better treatments and drugs.

          • Rune Valaker says:

            >>To compare different countries to see which has the best strategy is rather meaningless,,,,

            I beg to differ. To compare Denmark, Finland, Norway and Sweden is rather meaningful. They have about the same healthcare system, about the same ethnic composition and Sweden had fewer infected pr. capita than both Norway and Denmark.in the beginning of the pandemi. We also approximately have the same distribution of settlement patterns with some densely populated areas with subways, etc., and other areas with scattered settlement. The main reason why Sweden appears exceptional is due to the choice of strategy. A strategy our host seems to embrace, something he should think twice about

  10. Jerry says:

    Exactly! ?

  11. Börje Månsson says:

    Rune Valakar, I am not sure what the fourth alternative would be, but I guess you mean “The new normal” as described in the article.
    The new normal means covid-19 becomes like any other virus disease. It comes and goes on seasonal bases. Yes, this will probably be the end result of most virus outbreaks because your immunity will not last forever. This means the susceptible people will have inflow of people who has already had the disease but have lost their immunity. You can model this in SIR –system like this:

    dS/dt= -S*I*g*R0+k*(1-S)
    dI/dt= S*I*g*R0-g*I
    dR/dt= g*I-k*(1-S)

    Here 1/k represents the average time before you lose your immunity.
    Then you have a steady state solution with dS/dt=0, dI/dt=0, dR/dt=0 but with I>0.
    The steady state solution is

    1-S=1-1/R0
    I=k/g*(1-1/R0)

    K will be much smaller than g so I will be on a low level.
    In practice I will oscillate around this steady state value.

    1-S=1-1/R0 means you need herd immunity before you come to this situation.
    I would say this is a special case of alternative 2.

    • niclewis says:

      “your immunity will not last forever”

      It is true that for many virus infections immunity is not long lasting. But memory T-cell immunity against SARS-COV arising from infection in 2003 appears to still exist, which seems to bode well for long-lived immunity to SARS-CoV-2, although the strength of the immunity conferred is not currently clear.

      See Bert et al: https://doi.org/10.1101/2020.05.26.115832

      “infection with betacoronaviruses induces strong and long-lasting T cell immunity to the structural protein NP.”

      If this isn’t the case for SARS-CoV-2, or the T-cell immunity is too weak to be useful, and immunity to it is short lived – like that to common cold coronaviruses – then a vaccine won’t help much either, unfortunately.

    • Rune Valaker says:

      No, the fourth option is that the virus “burns out” (whatever that means) or changes to a less dangerous form, something that has happened before. That the virus has changed is already reported by Italian professionals: https://www.dailysabah.com/world/europe/covid-19-becoming-much-less-lethal-italian-doctors-say In either case, a “knock down” strategy is far preferable to letting the virus pass through the population to achieve herd immunity.

      • Andrew Carey says:

        That’s not a change in the virus. It’s a change in the viral load that the average infected individual being detected is carrying. It’s probably a result of the initial viral dose being smaller, perhaps because you caught it outdoors or were sharing someone’s air only briefly.

        • Rune Valaker says:

          You may be right. But the discussion here is “Sweden” which is portrayed as a pioneering country but whose strategy is beginning to appear as a huge mistake. Even Tegnell has now admitted that the strategy was wrong and that they should have introduced stronger measures in the beginning.

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