Look up what is in ALL usa vaccines that cause harm in everyone.
Antigens. But as you learned, they are in forms that rarely cause harm to anyone.
Look up what is ABSENT in japanese vaccines, so they do not cause harm (known anyway).
I think you may be confusing the mercury-poisoning cases from a Japanese company dumping mercury residue into a bay where fish became contaminated. Like the United States, thimersol use in Japanese vaccines is either extremely low, or absent entirely.
You probably get more mercury from a serving of canned tuna than you get from any vaccine:
Canned tuna: 0.128 ppm
Should You Avoid Fish Because of Mercury?