I would like to second @2135ar. When living in such close quarters with other students, it’s a breeding ground for rapid fire disease spread. Usually that means a cold or the flu, but sometimes is more serious (such as the princeton outbreak). I myself got swine flu back in '09 (that was no fun) during the wustl outbreak.
Also to be a bit of a downer, the strain the Emily Benatar had (the student who unfortunately passed away at wustl in 2012) was indeed Men B. As I recall, she had the old vaccination, but unfortunately the new one did not exist/wasn’t approved at that time.