[anovikov]

Super easy, they just have very, very few old people. Different population pyramids. Hence low fatality ratio. And low prevalence is just because vast majority of people are young and have it asymptomatically.

It may also play a role that asymptomatic carriers have lower chance of transmitting infection, so R0 in those countries is lower.

[riprock]

Thoughts on countries like Japan with a super-aged population but with low fatality ratio?

[anovikov]

Culture of discipline. If government says you to wear masks, you don't run a rally because not wearing a mask is your "human right". You wear a mask.