Though there is a vaccine for mumps, regularly there are outbreaks in the United States among the unvaccinated population. Most commonly, this is among people living in close-quarters on school campuses. Mumps is a viral infection that affects the salivary glands and is highly contagious.

Symptoms of the mumps virus develop a few weeks after expose. Primarily, you should look out for pain in swollen salivary glands on either side of the face. Other symptoms include pain with chewing and swallowing, fever, headache, muscle ache, weakness, fatigue, and loss of appetite (source). If you are experiencing these symptoms, seek treatment immediately. Mumps are most contagious for roughly nine days after symptoms appear. Alert your doctor that you believe you might have mumps so they can make arrangements to avoid further contamination of their waiting room and other spaces. Mumps can be contracted through saliva, which means it can be contracted by breathing in air contaminated by an infected person’s cough or sneeze.

Mumps in general are rare, and even rarer are complications from mumps, but some can be very serious. Mumps causes swelling in the body, in the salivary glands this is treatable, but it can also lead to swelling in the brain, pancreas, testicles, and membranes surrounding the brain and spinal cord (also known as meningitis). If you believe you have mumps and are experiencing pain in any of the aforementioned places, seek medical treatment as soon as possible, especially if the brain is concerned as untreated swelling in the brain can be fatal.

Additionally, if you’re pregnant, you should seek treatment for mumps as soon as symptoms arise. Untreated mumps, especially early on in pregnancy, can lead to miscarriage. Other complications include hearing and heart problems. These are usually not permanent, but should be treated as soon as problems arrive.

A two-shot vaccine is available to guard against mumps. A third shot is available to limit risk of infection even further, but two are sufficient for most people. The third shot is usually recommended for college students or those in the midst of an outbreak. People who should not get this vaccine are people who are allergic to neomycin, people with compromised immune systems, or women who are pregnant or trying to conceive within four weeks.