How often do outbreaks occur in on college campuses?
From 1980 to 1993, there were 21 outbreaks, three of which occurred in colleges. From 1994 to 1996, there have been 26 outbreaks, four of which occurred in colleges. Between 1986 and 1993, an outbreak was defined as five cases of the same serotype in 100,000 people with at least three occurring within three months. From 1994 to present, 10 cases of the same serotype in 100,000 people with at least three occurring within three months constitute an outbreak.