A CONTAGIOUS VIRAL infection, mumps reportedly affected nearly 200,000 people each year in the US before the introduction of the mumps vaccination program in 1967.1 After a two-dose vaccination program was implemented in 1989, reported mumps cases dipped to just a couple hundred to several thousand each year. However, prevalence of this once-dormant viral illness has surged in recent years due to an uptick in outbreaks among close-knit communities. Cases surged from 229 in 2012 to over 6,000 in both 2016 and 2017 due to outbreaks that mostly affected young adults on college campuses.1 This article revisits the mumps viral infection, including signs and symptoms, possible complications, treatment, and recent action taken by the CDC to help curb the recent spike in mumps outbreaks among people who are at increased risk to acquire the disease despite being fully vaccinated.

Clinical manifestations

Mumps is caused by a paramyxovirus. The incubation period is usually 16 to 18 days (range 12 to 25 days) from exposure to onset of signs and symptoms. Some patients have very mild or no symptoms and may not know they have the infection.2 Mumps typically starts with a few days of fever, headache, myalgia, fatigue, and anorexia.2 Patients may then experience unilateral or bilateral swelling of the salivary glands (parotitis).3 Parotitis typically reaches its peak level after 1 to 3 days and may last up to 10 days.4

Diagnosis

Mumps should be suspected in patients with typical clinical manifestations, such as parotitis or other salivary gland swelling, orchitis, or oophoritis, and relevant epidemiologic exposure with an individual with known or suspected mumps. Individuals who are known to be unimmunized are at highest risk for infection, though mumps should also be suspected among vaccinated individuals with relevant symptoms and epidemiologic exposure. Patients being evaluated for mumps should be placed on droplet precautions.5

Complications

Mumps can cause complications, especially in adults. Males who have reached puberty could experience orchitis, but this rarely leads to fertility problems.6 Other rare but potentially serious complications include encephalitis, meningitis, oophoritis and/or mastitis, pancreatitis, and deafness.3,6

Treatment and containment

There is no specific antiviral therapy for mumps, and most patients fully recover after a few weeks. Supportive care includes rest, over-the-counter antipyretics, and analgesics such as ibuprofen and acetaminophen.3 Advise patients to see their healthcare provider if they develop signs or symptoms of mumps.

Control of mumps transmission is challenging because the virus is present in saliva days before clinical parotitis occurs, and viral shedding can occur in asymptomatic individuals. Hospitalized patients with mumps should be isolated with droplet precautions until the parotid swelling has resolved.5 Outpatients should avoid contact with others from the time they are diagnosed until at least 5 days after parotitis starts.4 Advise patients to stay home from work or school and stay in a room apart from others during this time, if possible.

Prevention

Most people are fully immune to mumps once they receive two doses of the combined measles-mumps-rubella (MMR) vaccine. Parents are encouraged to ensure that their children receive two doses of the MMR vaccine before they start school. Children should receive the first dose at ages 12 to 15 months and the second dose at ages 4 to 6 years.3 Children may also get MMRV vaccine, which protects against measles, mumps, rubella, and varicella (chickenpox). This vaccine is licensed for use only in children who are ages 12 months through 12 years.7 College students, international travelers, and healthcare workers should all receive two doses of the MMR vaccine.3

A new recommendation

In October 2017, the CDC's Advisory Committee on Immunization Practices recommended that people previously vaccinated with two doses of a mumps vaccine (MMR or MMRV) who are identified by public health authorities as being part of a group or population at increased risk for acquiring mumps during a mumps outbreak should receive a third dose of a mumps-containing vaccine.8 A guidance from the CDC states that public health authorities should first identify groups of people who have or have likely had contact with a patient with mumps during the period in which the patient was contagious.9 These groups of people include coworkers who work on the same shift with the patient or socialize after work with the patient, athletes who share sports facilities or equipment with the patient, and students who share the same study group, social group, fraternity, or sorority with the patient.9 If these people are found to have an increased risk of contracting the disease, they should be vaccinated.9 To date, the evidence is insufficient to fully determine the effect a third MMR dose has on containing or shortening the duration of an outbreak.

After reaching more than 6,000 in 2016 and 2017, reported cases of mumps dropped sharply to 2,251 in 2018, according to the latest available data from the CDC.10 As of January 31, 2019, preliminary data from the CDC showed that 18 states had reported 58 cases of mumps.1

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