This literature marketed report as received from author regarding a Mumps outbreak on an university campus, refers to a 26 patients of unknown age and gender. On an unknown dates, 22 of the patients were vaccinated with 2 doses of measles, mumps, and rubella virus vaccine, live (manufacturer unknown), 2 patients had received 1 dose of measles, mumps, and rubella virus vaccine, live (manufacturer unknown) and 2 patient had received 3 doses of measles, mumps, and rubella virus vaccine, live (manufacturer unknown). No concomitant medications were reported. On an unknown date in 2011, 26 patients developed mumps who had previously received measles, mumps, and rubella virus vaccine, live (manufacturer unknown) vaccine. On 29-SEP-2011, the Department of Public Health confirmed by polymerase chain reaction (PCR) three cases of mumps among students recently evaluated at their university student health services with symptoms suggestive of mumps. An investigation by DPH, student health services, and the local health department identified 29 mumps cases. The presumed source patient was an unvaccinated student with a history of recent travel, where mumps was circulating. The student had mumps symptoms for more than 28 days before the onset of symptoms among the patients confirmed on 29-SEP-2011. On 25-AUG-2011, the presumed source patient, an unvaccinated male, aged 21 years, arrived at the university's student health services with fever and unilateral facial and jaw swelling. The initial diagnosis was cellulitis and antibiotics were prescribed. Approximately on 31-AUG-2011 (reported as, by day 6) after symptoms onset, the patient complained of testicular pain, and mumps was suspected. He had not been vaccinated against mumps and had traveled during the exposure period. He was referred for mumps serological testing, but did not follow through. His illness was not reported to the local health department when mumps was suspected. Approximately on 15-SEP-2011 (reported as 3 weeks later), a second student, the source patient's roommate, was treated at student health services for fatigue and unilateral pain and swelling of the jaw and neck. This patient, a male aged 21 years, with a history of receiving 2 doses of MMR vaccine, received a diagnosis of parotitis. Mumps serologies were drawn, and he was advised to isolate himself in his room for 5 days. Mumps immunoglobulin M (IgM) testing was negative, and immunoglobulin G testing was positive, a pattern that does not rule out acute mumps because the ability to detect IgM was poor in vaccine recipients. The local health department was not notified. When three subsequent cases of mumps were confirmed by PCR on 29-SEP-2011 at DPH, an investigation was initiated. During the outbreak period (25-AUG-2011 to 07-JAN-2012), investigators identified 29 cases that met the Council of State and Territorial Epidemiologists 2012 case definition of mumps. The outbreak period extended from the symptom onset date of the source patient through two incubation periods after the symptom onset of the last laboratory-confirmed case. The average incubation period of mumps was 16-18 days; Thus, the timing of the first five patients indicated that at least two generations of transmission had occurred by the time public health was notified. Case-finding activities included notifying health-care providers serving the affected community, requesting PCR testing for persons with clinically compatible symptoms, and alerting adjacent local health departments to notify DPH of suspected mumps cases. All patients had epidemiologic links to the university: 27 (93 percent) were students, one was a close contact of a student, and one was a public health staff member who assisted during a mumps vaccination clinic. Among the 29 cases, 13 (45 percent) were laboratory confirmed by PCR, one was confirmed by the presence of mumps IgM, and the remainder were confirmed on the basis of symptoms clinically compatible with mumps together with epidemiologic links to the university. Of the epidemiologically linked cases, 11 were negative and four were not tested by PCR. All viral specimens were genotype G, the predominant mumps genotype circulating. Eight patients (28 percent), including the source patient, were students who participated in organized sports. Among the 29 cases, 22 (79 percent) mumps illnesses occurred among persons previously vaccinated with the recommended 2 doses of Measles, Mumps, and Rubella Virus Vaccine, Live (manufacturer unknown) vaccine. Because the source patient was unvaccinated, this outbreak might have been prevented if the university had a prematriculation MMR vaccination requirement in place. Accessing the medical records of students suspected and confirmed to have mumps was complicated by federal privacy protections of education records. In addition, immunization efforts initially could have been targeted to unvaccinated or under vaccinated students if prematriculation immunization records had been available. This outbreak demonstrates that even persons who have received 2 doses of generic (TRADE) might not be protected against mumps, and highlights the importance of heightened clinical awareness and timely reporting of suspected mumps cases to public health authorities. The effectiveness of MMR vaccine to prevent mumps has been estimated at median of 78% for 1 dose and 88% for 2 doses. Although mumps outbreaks have occurred in populations in which many persons have received 2 doses of MMR vaccine, prematriculation MMR vaccination might prevent the introduction of mumps and limit its spread if it is introduced into a university setting. Colleges and universities should consider implementing prematriculation immunization requirements similar to those recommended by the College Health Association, including ensuring that students have documented receipt of 2 doses of MMR vaccine (2). Public health officials should be aware of disclosure limitations under FERPA and how these might impact communicable disease reporting requirements and timely investigation of outbreaks. Clinicians should be diligent about reporting suspected cases of mumps to local health departments, and PCR testing should be performed for vaccinated persons with suspected mumps. Additional information has been requested.