Uh... from what do you understand that? Sweden isn't even close. Their deaths/case ratio isn't too far off from New York. We have reasonably good evidence now that New York is maybe 30-50% of the way to herd immunity (plus or minus a factor of two or so).
New York has six times the per capita deaths that Sweden does. Just extrapolating and multiplying their current number by 3x6==18, that's about 35000 dead swedes until they get to herd immunity.
I genuinely don't understand the alternative world some people live in where Sweden has already beaten this. They're current curve is about 3 weeks behind most of Europe, largely due to the lack of lockdown that allowed the early outbreak to spread for longer.
That's a statement from a politician, not a scientific result. He's not predicting "almost there", he says they "could" reach herd immunity within a month. And that 30% with immunity number quoted is wildly off from the actual research already done on this stuff in Italy and New York. In fact the back of my envelope tells me that it requires an even higher asymptomatic undercount than even the Stanford study did.
This isn't evidence. You're reading spin. The article even tells you that.
Almost to herd immunity? No. They're at less than 1% infected (like most places), with more deaths per capita than the us despite a younger healthier population.
I read The Model Thinker some time last year. It includes a chapter on the SIR model used in epidemiology. The book states the basic mathematical model for working out how much of the population needs to be immune before 'herd immunity' is achieved is (R0 - 1)/R0.
I have heard R0 estimated around 4. So, technically you would need 3/4 of the population to be immune. The result of this being that R_t drops below 1 thus no longer becomes an epidemic and eventually either disappears or becomes seasonal.
