DD's best friend at nursery's baby sister has just been diagnosed with measles, DD had been kissing the baby whenever we meet. DD has had steroids over the weekend for her chest and has low immune system, she has had the 1st mmr but it's effects may be reduced by the steroids. The whole class has been exposed today, would getting her booster now be too late? or shall we just hope she doesn't get it and wait for her booster in 6 months?