Mumps (Parotitis)

Mumps is a vaccine-preventable viral infection transmitted by and affecting only humans. While the salivary glands (especially the parotid gland at the sides of the cheeks) are well known to be involved during a mumps infection, many other organ systems may also experience the effects of the virus infection.

• There is no cure for mumps, but the illness is of short duration (seven to 10 days) and resolves spontaneously.
• Prior to the introduction of mumps immunization, the highest incidence of new cases of mumps was reported in the late winter to early spring.

Medical historians believe that documentation of a clinical illness consistent with mumps dates back to Greco-Roman times. The first effective vaccine against mumps was introduced in 1948 and used from 1950 to 1978. Unfortunately, this vaccine strain had limited long-term immune memory effectiveness.

• The current strain used in the United States and worldwide provides 88% long-term immunity.
• The current childhood mumps immunization schedule recommends vaccination at 12-15 months old and a booster at 4-6 years of age.
• The mumps vaccine is commonly administered as part of a combination vaccine (MMR) and also provides protection against measles and rubella (German measles).

Prior to the routine administration of the MMR vaccine, approximately 186,000 cases per year were documented in the United States. With immunization, that number has fallen to 2,015 cases in 2015.

Mumps virus is a single strand of RNA housed inside a two-layered envelope that provides the virus its characteristic immune signature. Only one type of mumps virus has been demonstrated to exist (in contrast to the many virus types that can cause the common cold).

Mumps is highly contagious on the order of magnitude of both influenza and rubella (German measles).

• It is, however, less contagious than measles and varicella (chickenpox).
• It is transmitted only from human to human.
• Mumps has a rapid spread among members living in close quarters.
• The virus most commonly is spread directly from one person to another via respiratory droplets expelled during sneezing or coughing.
• Less frequently, the respiratory droplets may land on fomites (sheets, pillows, clothing) and then be transmitted via hand-to-mouth contact after touching such items.
• Animals cannot contract or spread mumps.

Risk factors for mumps include:

1. Failure to vaccinate completely (two separate doses) with exposure to those with mumps
2. Age: The highest risk of contracting mumps is for a child between 2 and 12 years of age.
3. Season: Outbreaks of mumps were most likely during the winter/spring seasons.
4. Travel to high-risk regions of the world: Africa, the general Indian subcontinent region, and Southeast Asia. These areas have a very low rate of immunization.
5. Weakening immune system: either due to diseases (for example, HIV/AIDS, cancer) or medication (oral steroid use for more than two weeks, chemotherapy)
6. Born before 1956: Generally, these individuals are believed to have experienced mumps infection in childhood. However, if they did not, they are at risk for adult mumps disease. Adult mumps is associated with a more intense disease and a higher rate of certain side effects (such as inflammation of testicles, or orchitis). A blood test may be obtained to determine immunity and is worthwhile if any doubt exists regarding prior mumps infection.

There is a 14-18-day period between contracting the mumps virus and the onset of symptoms and signs. Viral shedding is short-lived and a patient should be isolated from other susceptible individuals for the first five days following the onset of swelling of the salivary (parotid) glands.

The highest likelihood of spreading mumps covers the period of two days before the onset of symptoms and the first five days of parotid gland swelling and tenderness.

Routine cases of mumps last approximately seven to 10 days.

Nonspecific symptoms of low-grade fever, headache, muscle aches (myalgia), reduced appetite, and malaise occur during the first 48 hours of mumps infection. Parotid gland swelling characteristically is present on day three of illness. (The parotid gland is a salivary gland located anterior to the ear and above the angle of the jaw -- imagine a large set of sideburns.) The parotid gland is swollen and tender to touch, and referred pain to the ear may also occur.

Parotid gland swelling may last up to 10 days, and adults generally experience worse symptoms than children. Approximately 95% of individuals who develop symptoms of mumps will experience tender inflammation of their parotid glands.

Interestingly about 15%-20% of mumps cases have no clinical evidence of infection, and 50% of patients will have only nonspecific respiratory symptoms and not the characteristic described above. Adults are more likely to experience such a subclinical or respiratory-only constellation of symptoms while children between 2 and 9 years of age are more likely to experience the classic presentation of mumps with parotid gland swelling.

• The unique physical exam findings seen in those with mumps are swelling and tenderness of one or both parotid glands on the sides of the face.
• The parotid glands are embedded into the cheeks in front of the ear where a large set of sideburns would be.
• Less commonly affected are the salivary glands located under the lower jaw (mandible) or under the tongue (sublingual salivary glands).

Most cases of mumps are not complicated and thus may be managed by healthcare professionals such as

• pediatricians, internists, or family practice doctors.
• An infectious-disease specialist may need to be consulted for unusual health circumstances or medically complicated patients.

The diagnosis of mumps is primarily one of clinical acumen. Laboratory studies are generally done to support the clinical impression. The purpose of these laboratory studies is to exclude other viruses that may give a similar clinical presentation as well as to exclude very infrequently similarly presenting parotid gland enlargement (for example, salivary gland cancer, Sjögren's syndrome, IgG-4 related disease, sarcoidosis, side effects of thiazide diuretics, etc.).

The mainstay of treatment (regardless of age range) is to provide comfort for this self-limited disease. Taking analgesics (acetaminophen, ibuprofen) medication and applying warm or cold packs to the swollen and inflamed salivary gland region may be helpful.

There are four serious health complications of mumps: meningitis (infection of the spinal fluid which surrounds the brain and spinal cord), encephalitis (infection of the brain substance), deafness, and orchitis (infection of the testicle/testicles). All four complications may occur without the patient experiencing the classic involvement of the parotid gland.

1. Meningitis: More than half of patients with mumps will have meningitis, which may occur during any period of the disease. Generally, patients make a full recovery without permanent health side effects.
2. Encephalitis: Until the 1960s, mumps was the primary cause of confirmed viral encephalitis in the United States. Since the successful introduction of a vaccination program, the incidence of mumps encephalitis has fallen to 0.5%. Fortunately, most patients recover completely without permanent medical side effects.
3. Deafness: Preceding the mumps immunization program, permanent nerve damage resulting in deafness was not unusual. While occasionally bilateral, more commonly only one ear was affected.
4. Orchitis: This complication was the most common side effect of postpubertal males who contracted mumps. Severe pain (often requiring hospitalization for pain management) was one-sided in most cases. Some affected testicles atrophied (decreased in size), and some demonstrated impaired fertility. The "common knowledge" of sterility was actually rare. Previous concerns regarding mumps orchitis and later development of testicular cancer have not been proven. (Ovarian involvement has been reported to occur in some postpubertal women.)

Less frequent health complications of mumps infection include arthritis, infection of the pancreas, infection of the myocardium (heart muscle), and neurological conditions (for example, facial palsy, Guillain-Barré syndrome, etc.).

Mumps is generally a benign self-limited disease that produces lifelong immunity. Severe medical side effects are extremely rare; more common complications (though still relatively rare) are listed above.

Non-immune women who contract mumps during the first trimester of their pregnancy have an increased rate of miscarriage, but infants carried to term have no higher risk for congenital malformations.

Since there is only a single mumps virus in existence, lifelong immunity is generally acquired after mumps infection. Ways to document mumps immunity include

1. born before 1957,
2. diagnosis of mumps by a physician, and
3. laboratory confirmation of previous mumps virus exposure.

Mumps immunity after complete vaccination is approximately 88%. A boost in immunity occurs when exposed to an individual with an active case of mumps.

Prior to the start of mumps vaccination in 1948, outbreaks during the winter/spring would commonly affect young schoolchildren with secondary spread to other family members not yet immune. Until an effective vaccine program was introduced, isolation of the infected individual was the only public health control option. The current MMR strain used in the United States and other developed countries was licensed in 1967. Another strain is more commonly used in developing countries. Both strains provide approximately 88% immunity following the two-vaccination schedule detailed below. A single dose of mumps vaccine provides immunity to only 78% of recipients.

The Centers for Disease Control and Prevention (CDC) recommends a combination vaccine (MMR) for children at 12 to 15 months of age with a booster dose at 4 to 6 years of age. During periods of possible mumps outbreaks, the booster dose may be administered after a minimum of 28 days following the initial immunization. The MMR immunization is designed to prevent measles, mumps, and rubella (German measles). Adults born after 1956 should receive at least one MMR vaccination. Those born prior to 1956 are generally found to have acquired natural immunity and no vaccination is necessary.

More common side effects of the MMR vaccine include

• stinging/burning at the injection site,
• mild fever, and
• mild skin rash.
• The fever and skin rash most commonly develop five to 12 days postvaccination and occur more commonly after the first vaccination.
• Some recipients of the vaccine will note mild enlargement and tenderness of local (for example, neck) lymph nodes.

It should be noted that these relatively common side effects are considerably less severe than acquiring any of the three illnesses the MMR vaccine is designed to prevent.

In extremely rare situations, more severe reactions affecting the nervous system, gastrointestinal system, digestive organs, the skin, and others may occur.

A very small population should not receive the MMR vaccine.

• These include individuals with a compromised immune system (HIV/AIDS, cancer, those receiving more than two continuous weeks of oral steroids) or
• who are allergic to any component of the vaccine, including gelatin or neomycin.

MMR vaccines are very unlikely to produce a severe reaction to those who are egg white allergic. Daily use of inhaled steroids (such as those used to control certain pulmonary diseases such as asthma, COPD, etc.) is not a contraindication to the MMR vaccine. Patients with a mild illness (for example, the common cold) may safely receive the MMR vaccine. Conception should be avoided until at least 28 days following vaccination.

Multiple international studies have not demonstrated any causative relationship between the administration of the MMR vaccine and the development of autism, disproving previous erroneous theories.