Should we get a 2nd measles vaccination? Ages 90, 71, 69.

Depends where you are. If I was in an area where measles is breaking out, I would ask the MD if it is a good idea for a booster.

If one was born during or before 1956, you are presumed to be immune, because many children had the diseases then. If not sure you ever had the measles, check with your primary doctor as to whether you need one shot, orr one shot with booster.