Does the MG vaccine work?

[BLaBauve]

My flock may have MG (pending lab results), and I was wondering if there was any benefit to giving them to MG vaccine.

My questions are:

Would it benefit my already affected flock to receive the vaccine?
Could I give the vaccine to chicks that I'd like to integrate into my flock at some point?

I do not breed or sell eggs, just eat them myself. I have a small flock of hens but would like to a few more at some point.

Thanks!