I always say **Bless You**. I used to say **gesundheit** [used to wish good health to a person who has just sneezed.] More apt, but German is not understood much in the States anymore.
Just as a fact point, it was believed, incorrectly, that when you sneezed you were close to death. People said "Bless You" as a prayer to protect the sneezer.
Since we know that is not true now, the idea of saying a blessing seems out of step with current knowledge.
Not against saying it, this is just something to know.