 [ Symptoms ] how contagious is  amumps if you have 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 [ Disease ] 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>