Centers for Disease Control and Prevention (CDC) clinical case definition for mumps: illness with acute onset of unilateral or bilateral, tender, self-limited swelling of the parotid or other salivary gland, lasting ≥2 days, without other apparent cause


  • In the prevaccine era, 90% of all children contracted mumps virus infection by 14 years of age.
  • Incidence of this once very common disease has declined dramatically since the advent of universal childhood immunization.
  • Outbreaks, however, continue to occur, and cases in the United States have ranged from several hundred to several thousand cases annually.
  • Since 2014, >1,000 cases per year have been reported in the United States, with >6,000 cases reported in 2016.
  • Most outbreaks have been linked to being in a close crowded environment and intense exposures, such as universities, sports teams, and close-knit religious communities.
  • Outbreaks can occur in highly vaccinated communities, particularly in very close-contact settings such as college dormitories and camps.
  • High vaccination rate helps limit the severity, size, and duration of mumps outbreaks.


  • Two combination mumps vaccine are used:
    • MMR: measles, mumps, rubella
    • MMRV: measles, mumps, rubella, varicella
  • A single 0.5-mL SC injection of live mumps vaccine (MMR or MMRV) is recommended at 12 to 15 months.
  • A second vaccination is recommended between 4 and 6 years of age.
  • The efficacy of 2 doses of vaccines is estimated at approximately 80–90%.
  • Primary vaccine failure and waning vaccine-induced immunity have been reported.
  • During mumps outbreaks, a third dose of vaccine may be recommended by public health authorities for targeted populations in conjunction with CDC guidance. Studies indicate no increase in adverse effects after a third vaccine dose and improved control of mumps outbreak.
  • The first dose of MMR vaccine can be associated with fever and rash:
    • These symptoms occur 7 to 12 days after immunization.
    • Measles component is usually the culprit.
  • Both MMRV and MMR vaccines, but not varicella vaccine alone, are associated with increased outpatient fever visits and seizures 5 to 12 days after vaccination in 12- to 23-month-olds, with MMRV vaccine increasing fever and seizure twice as much as the MMR + varicella vaccine.
  • Vaccine should not be administered to children who are immunocompromised by disease or pharmacotherapy, as well as to pregnant women.
  • If a child has recently received immune globulin (IG), administration of MMR vaccine should be delayed (for 3 to 11 months depending on the dose of immune globulin).
  • Children with HIV infection who are not severely immunocompromised (age-specific CD4+ T-lymphocyte percentages of 15% or greater) should be immunized with the MMR vaccine.
  • One attack of mumps (clinical or subclinical) usually confers lifelong immunity.
  • Links of the MMR vaccine to autism by Andrew Wakefield in a 1998 Lancet publication have now been exposed as fraudulent, and multiple studies have documented no association between MMR vaccine and autism.


  • Epidemic parotitis is caused by mumps, an RNA virus in the Paramyxoviridae family.
  • Other viral causes of parotitis include Epstein-Barr virus, cytomegaloviruses, influenza, parainfluenza, and enteroviruses.
  • Parotid enlargement can be an initial sign in HIV-infected children.
  • Bacterial cases are usually secondary to Staphylococcus aureus (suppurative parotitis).
  • Streptococci, gram-negative bacilli, and anaerobic infections are also possible.
  • Rare childhood cases may be secondary to an obstructing calculus, foreign body (sesame seed), tumors, sarcoid, Sjögren syndrome, or various drugs (antihistamines, phenothiazines, iodine-containing drugs/contrast media).


  • The virus is spread by contact with respiratory secretions.
  • The mumps virus enters via the respiratory tract, and a viremia ultimately ensues.
  • The virus spreads to many organs, including the salivary glands, gonads, pancreas, and meninges.
  • Period of communicability: 7 days before to 9 days after onset of parotid swelling
  • Most communicable period: 2 to 3 days before to 5 days after onset of parotid swelling
  • Incubation period: 12 to 25 days after exposure (16 to 18 days most common)
  • Humans are the only known host for mumps.


  • Salivary adenitis
    • Most common manifestation of mumps
    • 1/3 of cases occur subclinically.
  • Epididymoorchitis
    • Up to 35% of adolescent mumps cases are complicated by orchitis.
    • Orchitis develops within 4 to 10 days of the onset of the parotid swelling.
    • Sterility is uncommon.
  • Aseptic meningitis
  • Pancreatitis
    • Mild inflammation is common.
    • Serious involvement is rare.

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