Right now Norway 0.7 and denmark 0.9 has a "R" number below 1. Sweden is the last days getting down to around 1.0.
But now when these countries opens up the calculation is that most of them with a limited opening will fast reach around a R number of 1.2.https://www.dn.se/nyheter/sverige/darfo ... nlanderna/
The fact that Sweden has introduced milder coronary restrictions than other countries has attracted attention. Now it turns out that Sweden also reports the spread of infection in other ways than, for example, Norway and Denmark. "That's not a good speech," says state epidemiologist Anders Tegnell about the neighboring countries' figures.
How many people each infected person in turn infects is a crucial task when gaining control of the covid-19 spread.
The spread of infection is indicated by the so-called reproduction number, R-zero. If it is above 1, it means that each infectious person infects more than one additional person, and the spread of disease continues. If, on the other hand, it is less than 1, every infectious person infects less than one person on average, and the epidemic is cleared.
Different infections are given different R-zero values. Seasonal flu is around 1.5, ebola at 2 and the new corona virus (sars-cov-2) is believed to be around 2.5.
The most contagious disease affecting humanity is probably the measles, which has an R-zero value of around 15, that is, each infectious person infects on average 15 others.
But: all this applies only at the beginning of a spread of infection. Gradually, different things happen that change the conditions.
On the one hand, parts of the population become immune (or receive vaccines), and on the other, various measures are taken in society to reduce the spread of infection, such as social distancing, closed workplaces and increased hand hygiene. Then you talk about R-e, or just the R-number.
- What matters most is that if it is below 1, the infection will subside. If you do nothing, it is initially 2.5 in this case, and the infection is gaining momentum, says Tom Britton, professor of mathematical statistics with a focus on the spread of infection.
In Norway and Denmark, which have imposed stricter restrictions than Sweden, there is now talk of slowly starting to open society again after Easter. It is believed that they have been given sufficient control over the spread of infection to be able to do so.
Prior to this softening, great focus has been placed on the R's. In Norway, Health Minister Bent Høie said this week that it is now at R 0.7. The Danish infection control authority SSI states that the figure is 0.9.
The goal is not to get too high above 1 when you start to open schools and other things. In Denmark, Kåre Mølbak at SSI says that he has raised a R-figure of 1.2 when the schools open and hope to be able to turn down from there.
In Germany and Austria too, great importance has been placed on the spread of infection.
In Sweden, on the other hand, the Public Health Agency has not regularly used this value in its reporting
- I would think that the Swedish figure right now, at least this past week, is very close to 1, possibly a little over, says Swedish state epidemiologist Anders Tegnell.
But he is hesitant to use the R-number, because it varies so much, basically day by day.
- You choose two measurement points with four five days in between, and if the spread has increased it is above 1, if it has decreased it is below 1. You have to have quite a few points before you get a stable figure.
- That's not a good speech. It is better to look at the trends. It gives a better picture of where you are going somewhere, says Tegnell.
By Thursday, 9,100 people in Sweden had been confirmed to be infected. These are largely people who have sought care and / or work in healthcare.
In fact, Tom Britton believes that there are significantly more Swedes infected. With the help of mathematical modeling, he concludes that the proportion in Stockholm should now be about 20 percent - not contagious now, but which has the virus or has had it.
- There is a lot of uncertainty, but most people agree that it is a large proportion. The share is not below 10 percent and not over 50, says Britton.
The Public Health Authority has made a first preliminary assessment of how many people may be infected. Of a representative sample of 773 people in the Stockholm area, 2.5 percent were found to carry the virus.
- But the proportion who have had or have the virus is significantly higher. The infection has been around for a while and you carry the virus for maybe five days, says Anders Tegnell.
When asked the question of how many he himself thinks it might actually be about, he answers with "a wild guess":
- The doubling time is 6–7 days, so just based on that, the proportion is probably up to 10 percent now. How many who have had it before is more trixical, we do not really know.