Epidemiology Unit

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photo of young man with mumps


Mumps is circulating in San Diego County. The number of cases reported in the County in 2019 is the highest in 25 years, and an elevated number of cases are being reported in 2020. (See box at right for the latest local case information.)

Neighboring counties have also reported recent increases in mumps cases. Los Angeles County and Orange County noted an increase in mumps cases in 2019.

Nationally, 3,474 mumps cases were reported in 2019 to the Centers for Disease Control and Prevention (CDC). The Mexican Ministry of Health reported 8,085 cases of acute parotitis/mumps in Mexico in 2019, including 900 cases in Baja California.  An increased number of these cases continues to be reported in Baja California in 2020, with 138 cases reported through February 8, 2020.

Through March 31, 2020, fifteen mumps cases were reported in San Diego county in 2020.  Six cases are associated with an outbreak among students at San Diego State University.  In 2019, there were 66 mumps cases reported in San Diego County. Six cases were hospitalized and there were no deaths. Cases ranged in age from 9 months to 79 years (median 28 years) and 40 (61%) are male.  The next update will be provided in May. 

The following groups in San Diego County are currently recommended to have a third MMR vaccination as part of outbreak control:



Mumps causes puffy cheeks and a tender swollen jaw. This is because salivary glands under the ears on one or both sides of the head become swollen (this is often called parotitis). Other symptoms that might begin a few days before parotitis include:

  • fever
  • headache
  • muscle aches
  • tiredness
  • loss of appetite

Symptoms usually appear 16-18 days after infection, but this period can range as much as 12-25 days.

Some people who get mumps have very mild symptoms (like a cold) or no symptoms at all. They may not even know they are sick.

Occasionally, mumps can cause more severe complications.



Mumps is a contagious disease caused by a virus. It spreads through direct contact with saliva or respiratory droplets from the mouth, nose, or throat. An infected person can spread the virus by:

  • coughing, sneezing, or talking
  • sharing items that may have saliva on them, such as water bottles or cups
  • participating in close-contact activities with others, such as playing sports, dancing, or kissing
  • touching objects or surfaces with unwashed hands that are then touched by others

An infected person can likely spread mumps from a few days before their salivary glands begin to swell to up to five days after the swelling begins. A person with mumps should limit their contact with others during this time. For example, the person should stay home from school and not attend social events.



Mumps can occasionally cause complications, especially in adults.

Complications can include:

  • inflammation of the testicles (orchitis) in males who have reached puberty; this may lead to a decrease in testicular size (testicular atrophy)
  • inflammation of the ovaries (oophoritis) and/or breast tissue (mastitis)
  • inflammation in the pancreas (pancreatitis)
  • inflammation of the brain (encephalitis)
  • inflammation of the tissue covering the brain and spinal cord (meningitis)
  • deafness

Neither inflammation of the testicles nor inflammation of the ovaries caused by mumps has been shown to lead to infertility.



The best way to prevent mumps is by getting the MMR (measles, mumps and rubella) vaccine. Two doses are recommended—one at 12-15 months of age and another at 4-6 years of age. During a mumps outbreak, public health authorities may recommend a third dose of MMR vaccine for groups of people determined to be at increased risk for acquiring mumps.

For more information about mumps and the vaccine that protects against it, see the Resources for the Public section below.


Resources for the Public

Centers for Disease Control and Prevention:

California Department of Public Health Immunization Branch:

County News Center:

Mexican Ministry of Health:


Resources for Healthcare Providers

NOTE: For more information, including specific recommendations concerning diagnosis, specimen collection, caring for patients with mumps and related issues, please refer to the CAHAN San Diego Health Advisory Update #3 (Mumps in San Diego County) below, and the
Mumps Job Aid (11/20/19).

Suspected mumps cases should be reported to the San Diego County Epidemiology Unit at (619) 692-8499 during business hours, or by faxing a Confidential Morbidity Report to (858) 715-6458, during all hours.

Centers for Disease Control and Prevention:

CAHAN Alerts for Healthcare Providers:


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For more information, contact the Immunization Unit at 1-866-358-2966 and press 5 at the prompt, or send us an e-mail.