the mmr offers good protection. but unfortunately not 100%. mumps is contagious but i do not know what stage of the illness your grandchild is in so this question needs to be addressed to the medical provider who made this diagnosis. <link>
how contagious is 'mumps' if you've had your mmr vaccination? . i have 1 grandchild out of 11 that has developed mumps. he has had his mmr. is it safe to have him and his siblings over with the other family members?