COLUMBIA, Mo. (AP) — Officials say at least 73 confirmed and probable cases of mumps have been reported at the University of Missouri.

The Columbia Missourian reports that many of the cases of the viral infection are linked to the school’s Greek life community.

The outbreak began in early November with four confirmed cases.

The executive director of the university’s health center says all infected students have been vaccinated, but the vaccine does not prevent 100 percent of infections.