Did mumps vaccine cause outbreak?

Mumps outbreak hits Fordham University:
nypost.com/2014/02/21/mumps-outbreak-at-fordham-university/

From the article:
“The thing is, just to get into Fordham you need to be vaccinated for mumps. So nobody knows if those kids got a bad vaccine or what,” Agostino said. “I just know I’m going straight to the health center if I see any symptoms.”
Fordham noted that the widely available mumps vaccinations do not guarantee 100 percent immunity.
“All of the students who were tentatively diagnosed with mumps had been vaccinated,” the university said in a statement. “Vaccinations do not offer 100 percent protection.”

uhhmmmm
hmmmmm
what could the answer be....

Yes?

Poor Bill Gates is having the same problem in India with his polio vaccine.

What could be the problem?