1/ Keep hearing I shouldn’t be citing Iceland’s data. Because that country is too small.

Here is why that makes no sense.

2/ Size of a country irrelevant to whether it’s scientific discovery is sound.

I am not citing Iceland as a paradigm.

Rather, I am citing a scientific discovery that happened to be made by people in Iceland.

That discovery doesn’t cease to be true because Iceland is small.

3/ Iceland sequenced virus samples from all of their cases and so was able to map the trajectory of spread.

They’ve done this for about ~1900 cases. Based on this, they concluded that it “crystal clear” that children were much less likely to be infected & to transmit.

4/ So, unlike other studies which had to guess about the direction of transmission, Iceland was able to confirm direction.

And doing that revealed that pediatric heterogeneity is real.

None of this has anything to do with the size of Ireland.

5/ Now, you could say “But the only reason Iceland observed what it did is because it’s small.”

But that would be nonsense.

6/The smaller size of Iceland could help explain why they’ve had an easier time managing disease overall.

But that would apply *across the board to all cases.* Not JUST to pediatric transmission.

Size can NOT explain away pediatric heterogeneity.

7/ You might also be worried that Iceland’s n is too small. But the relevant n is not the number of people who live in the country where the study performed. But the number of people in the study.

Iceland has mapped the virus for ~1900 infections. That is a big n.

8/ The n is certainly big enough to give us confidence in the results given their starkness.

17% of Iceland are under 15.

Yet, out of 1900 infections—which reflected random representative testing, not just symptomatic—less than 1% of transmission was due to children.

9/ The n is big enough such that these results would be inexplicable if the pediatric homogeneity hypothesis were true.

This is evidence that that hypothesis is false.

10/ In contrast, the pediatric heterogeneity hypothesis predicts the results that Iceland observed.

This is evidence that that hypothesis is true.

11/ Yes, bigger and bigger n always better. But the cynicism of people going on TV and touting a study with an n of 12 but balking at Iceland is simply stunning.

12/ So, in short, just as you wouldn’t ignore a finding about gravity because it was reached by scientists in a smaller country—you have no damn basis for rejecting a robust finding regarding pediatric heterogeneity simply because the scientists who discovered it live in Iceland.