Mumps is a contagious viral infection caused by the mumps virus. Since the introduction of the mumps vaccine in Canada in 1969, and the success of immunization programs ever since, cases of mumps in Canada have decreased by more than 99%. But mumps cases and outbreaks continue to occur in Canada and mumps remains endemic in many countries worldwide.

While some people who have mumps will not have symptoms or will have only very mild symptoms, the most common symptom of mumps is the swelling of the salivary glands. These glands are located just under the ears, and when they become inflamed, they can bulge and lead to tenderness in the jaw, as well as pain while eating. Other symptoms can include fever, headache, tiredness, sore muscles, dry mouth, and loss of appetite. In severe cases, mumps can lead to meningitis (inflammation of the lining of the brain and spinal cord) and encephalitis (inflammation of the brain). Rarely, both of these conditions can lead to permanent neurological problems, such as seizures and paralysis. Permanent deafness is also a potential side effect of mumps infection. However, this is also rare. Mumps can also lead to inflammation of the testicles (orchitis) and ovaries (oophoritis). In rare cases, this inflammation can lead to infertility (the inability to have children).

The mumps virus enters the body through the mouth or nose. Mumps is spread through close contact with others (e.g., coughing or sneezing next to someone, or sharing personal items such as drinks), or through coming into direct contact with an infected person’s mucus or spit and then getting these fluids in your nose or mouth.

While anyone can catch mumps, people who have weakened immune systems (who are immunocompromised) and/or who have chronic health conditions tend to experience more severe mumps infections.