Japan has a different medical system, different levels of adherence, different cultural hygiene standards, different exposure risk profiles for different pathogens.

Comparing the U.S. to Japan, or any other system for that matter, with a simple “well the vaccine schedule is different there” is simplistic and almost certainly not useful.

What is useful is to compare the U.S. with and without a certain vaccine or when delaying certain vaccines.

And we know how that plays out because all these vaccines have been added because of specific threats and actual diseases faced by Americans.