Strep throat is very contagious. I had it a little over a year ago and was miserable. My 3 year old (at the time) got it a few weeks after I did. My husband and 9 year old, however, did not as they were either at school or work most of the time.
I don't think there is much you can do about anyone else getting it besides the usual hand washing, covering your mouth when coughing...etc. I know that neither one of my boys will stay in bed away from the rest of the family while sick.
My husband lost his spleen many years ago and cannot fight off strep so if any of us get it he immediately goes on antibiotics....lucky him. He has never experienced strep ever!
Take care and I hope y'all don't get sick.