A mumps outbreak associated with San Diego State University has expanded to 14 confirmed cases and one probable case, according to San Diego County data through Wednesday. The count is a snapshot of a continuing investigation, not a final total. Public-health teams are notifying people identified as close contacts while SDSU, the County and state health officials coordinate vaccination and campus messaging.
Mumps spreads most efficiently during close, face-to-face contact. Respiratory droplets and saliva can move between people who are talking, coughing or sneezing within a few feet, and the social density of a university can create repeated opportunities for exposure. The County first announced the campus outbreak Sept. 18. It cautions that campus outbreaks can continue for several months rather than ending when one cluster is identified.
The characteristic symptom is swelling and tenderness around the jaw, caused by inflammation of the salivary glands. Fever, headache, earache and fatigue can precede that swelling. Anyone who develops symptoms should avoid contact with others and arrange testing through a health-care provider; SDSU students can contact Student Health Services. Isolation while awaiting results reduces the chance of passing the virus on.
Most infections do not lead to severe complications, but rare outcomes include meningitis, hearing loss and effects on fertility. There is no medicine that clears the virus after infection. Clinical care focuses on symptoms, while the public-health response tries to interrupt transmission through isolation, contact notification and vaccination of people whose immunity may have declined since childhood.
For people whom investigators identify as close contacts, the County recommends a third dose of the measles, mumps and rubella vaccine. That additional MMR dose is an outbreak-control measure intended to boost protection that may have waned. It cannot reverse an infection that has already begun, and it does not mean the routine two-dose childhood schedule has failed for everyone.
SDSU says it is purchasing additional vaccine, encouraging identified contacts to be vaccinated and distributing information across campus. Those steps work on different timelines. A message can prompt a symptomatic student to stay home immediately; vaccination strengthens the population response over time. Neither substitutes for testing when symptoms appear or for answering a contact investigator's call.
People who suspect exposure but have not received a County notice should monitor for symptoms and contact a provider if they become ill. The absence of a notification does not prove that no exposure occurred, because an infected person's full contact network may be difficult to reconstruct. At the same time, proximity to campus alone is not evidence of infection, and the reported count should not be read as a campuswide attack rate.
The next useful measure is not simply whether the case total rises. Investigators will watch when symptoms began, whether new cases are linked to known contacts and whether transmission moves beyond the existing network. Those details determine whether the outbreak is slowing. For students now, the practical rule is narrower: take jaw swelling and fever seriously, separate from others and seek testing before returning to shared rooms.