The fact that the number of cases has been increasing in Sweden recently doesn’t show it hasn’t reached herd immunity. It’s true that, if a place has reached herd immunity, the daily number of *infections* should go down, but cases are a very noisy indicator of infections. 1/n

If you look at daily ICU admissions, which is a much less noisy indicator of infections (though with a lag), then it’s clear that you can’t draw any conclusions about herd immunity from the recent increase in the daily number of cases. 2/n

If we had data on daily ICU admissions disaggregated by region and we knew how many of them are imported cases, we *may* be able to rule out herd immunity (although I doubt it), but we don’t and therefore we can’t. This shouldn’t even be controversial. 3/n

Of course, I can think of many hypotheses that would explain why the number of daily ICU admissions has remained very low for weeks despite the absence of herd immunity, that’s not the point. The point is that we have no idea whether any of them are true. 4/n

So this *doesn’t* mean that Sweden has reached herd immunity. It may be that, in the next few weeks, daily ICU admissions are going to increase again. But even if this happens, it won’t change the fact that, *at the moment*, we can’t rule it out. 5/5