Belgium, the Netherlands, and Israel are all slightly less dense than South Korea, and more dense than Japan. Yet all three have significantly lower flu/pneumonia death rates than either South Korea or Japan.

Bangladesh also has a slightly lower flu/pneumonia death rate than Japan, even though it has 3x the density (though Bangladesh has a somewhat lower life expectancy (72) than Japan (84); Belgium, Netherlands, and Israel are all fairly close (80+) to Japan).