Mumps–It’s Back!

OUTBREAK MANAGEMENT
A mumps outbreak is defined as three or more cases linked by time and place.⁴ The keys to managing an outbreak are to define the population(s) at risk and their transmission setting(s) and to rapidly identify and vaccinate vulnerable individuals without evidence of immunity.⁴

Presumptive evidence of mumps immunity includes¹¹
• Documentation of vaccination with two doses of live mumps virus–containing vaccine
• Laboratory evidence of immunity
• Laboratory confirmation of disease
• Birth year before 1957.

Documentation of two doses of MMR constitutes evidence of adequate vaccination for school-age children and adolescents and for young adults attending postsecondary institutions. During an outbreak, susceptible (ie, unvaccinated) students should be excluded from attendance until they have been vaccinated; those with one dose may attend but should receive the second dose.⁴ Those declining vaccination for medical, religious, or other reasons should be excluded until at least 26 days after the onset of parotitis in the last person with mumps at the institution.²⁴

If the outbreak threatens the wider community (eg, preschool-age children and adults), a second MMR dose should be considered for children ages 1 to 4 or for adults who have received one MMR dose. Similarly, MMR vaccination should be considered for adults born before 1957 who have no other evidence of immunity and are at risk for exposure to the virus.¹¹

In the workplace, health care workers’ (HCWs’) immunity status should be known, documented, and accessible in advance of an outbreak.¹¹ If an HCW without evidence of immunity is exposed to mumps, he or she should be excluded from patient care from the time of first unprotected exposure through the 25th day after the last exposure.²⁵ Although individuals born before 1957 are generally considered immune, if a nosocomial mumps outbreak occurs, the two-dose MMR regimen should be administered to these HCW as well.⁴

In 1991, the US military began to immunize recruits routinely with MMR, regardless of their immunization status.²⁶ During the 2006 mumps outbreak, the incidence of mumps among military personnel was minimal compared to that among their civilian counterparts—perhaps due to administration of a third MMR dose to an unknown number of recruits.²²

CDC researchers studied the impact of a third MMR dose for mumps outbreak control in 2012 and concluded that, while a third dose may help control outbreaks among populations with preexisting high two-dose vaccine coverage, further study is needed.²⁷

Although insufficient data exist on which to base a recommendation for or against a third MMR dose for mumps outbreak control, the CDC has issued guidance for public health departments for targeted administration during outbreaks. Considerations ­include
• Intense exposure settings
• High two-dose vaccination coverage (ie, > 90%)
• High attack rates (> 5 cases per 1,000 population)
• Evidence of ongoing transmission for at least two weeks in the target population.⁴

TREATMENT
There is no specific treatment for mumps. Care is supportive and in the outpatient setting includes rest, cold or heat to the affected areas, and OTC pain relievers. Ice can be used to help relieve the pain of orchitis. Acidic foods may stimulate the parotid glands, causing pain and difficulty swallowing, and should be avoided.

Isolation of infectious patients is vital to preventing the spread of mumps.⁴ In the clinician’s office, a separate waiting area should be used for a potential mumps patient, or the patient should be located at least three feet from other patients and asked to wear a surgical mask. HCW working with potential mumps patients should follow droplet precautions (eg, wear personal protective equipment) in addition to standard precautions and should be hypervigilant about hand washing.²⁴

CONCLUSION
Mumps is a usually benign, self-limited infectious disease that can potentially result in serious complications. It is also prone to periodic outbreaks. Control of mumps can best be accomplished by remembering these five “Ps”:
• Prevention—through widespread two-dose MMR vaccination
• Parotitis—recognize it as the primary symptom of mumps and make the diagnosis in a timely manner
• Persistence—in making the diagnosis clinically and in weighing laboratory results within the context of clinical disease
• Personal protective equipment—use it consistently in the health care setting or as needed in the home
• Protection—isolate patients with mumps to avoid spreading the disease