A person has 3 children aged 7, 5, and 2 years. None of them has received MMR vaccine. Now the child aged 2 has developed mumps. Other two children are in contact with the child with mumps for last 5 days.

Is it rational to give MMR now to the other two unaffected children? Will it protect them from getting mumps? After how many days the affected child be given MMR?