[mattnewton]

This is super interesting. My entirely unqualified gut reaction is that this is cultural- that Japanese people take infectious disease seriously and test+quarantine after experiencing symptoms or traveling at all, having already handled SARS outbreaks before, and many Americans are still debating whether the pandemic is real, and that behavioral difference is enough. I don’t know how to test that. But it could also just be as simple as Americans being less healthy.