sorry, the last sentence, I meant to say: In the Japanese society, sneezing is typically considered not that "clean" so we don't say much to people who sneezes...

It's a good question. Unlike the many countries, there is no standard saying in response to sneezing like "Bless you" or "Gesundheit" in Japanese. So either nothing (to strangers) is said, or "are you cold (Samui)”？or "are you ok" (Daijoubu)? to people you know can be said (if so desired). But these saying are not only limited to responding to sneezing. In the Japanese society, sneezing is typically not considered not that "clean" so we don't say much to it.