• Children's Center

    Infectious Diseases A-Z: Mumps outbreaks in the U.S.

a little baby with a swollen cheek because of mumps
The Arkansas Department of Health is investigating 2,918 confirmed cases of mumps and reports some of those cases involved children and adults who were immunized.

Mayo Clinic infectious diseases specialist Dr. Pritish Tosh says, "The measles, mumps and rubella vaccine (MMR) is very good in preventing mumps but not perfect. Often we see a large group of people and some of them are vaccinated, but then mumps is introduced to that population by people who aren't vaccinated and they act as amplifiers of the infection. There are going to be some who were adequately vaccinated, but, because it's not 100 percent effective for mumps, you start to see cases — not just in people who have not been vaccinated, but also in some people who have been adequately vaccinated."

Watch: Dr. Pritish Tosh talks about mumps vaccines.

What is mumps?

Mumps is a contagious viral illness that typically starts with a few days of fever, headache, muscle aches, tiredness, and loss of appetite, followed by swollen salivary glands. "Most people who get mumps get swelling in the neck area, and it causes a fever. And, for most people who get mumps, that’s the end of it. They get better on their own," says Dr. Tosh. "However, there are several complications. This used to be the No. 1 cause of sensorineural hearing loss in children and can cause infection in the brain."

Complications from mumps include:

  • Meningitis (infection of the covering of the brain and spinal cord)
  • Deafness (temporary or permanent)
  • Encephalitis (swelling of the brain)
  • Orchitis (swelling of the testicles) in males who have reached puberty
  • Oophoritis (swelling of the ovaries) and/or mastitis (swelling of the breasts) in females who have reached puberty

The best prevention is vaccination. The Centers for Disease Control and Prevention (CDC) recommends children get two doses of MMR vaccine, starting with the first dose at 15 months and the second at 4 to 6 years. Teens and adults also should also be up to date on their MMR vaccination. The CDC says there has been a 99 percent decrease in mumps cases since the mumps vaccination program in 1967.