Health Advisory
DPH REMINDS PROVIDERS TO LOOK OUT FOR MUMPS AS DPH INVESTIGATES OUTBREAK AMONG SCHOOL-AGE CHILDREN IN NEW CASTLE COUNTY, DELAWARE

Summary

This Health Alert Network (HAN) Advisory is to remind primary health care providers in Delaware that mumps outbreaks can still occur in communities of people who previously had one or two doses of MMR vaccine. This is particularly common in close-contact settings. Vigilance is needed to identify mumps cases early and prevent outbreaks.

Background:

High vaccination rates among Delaware children has resulted in only very few cases of mumps reported each year (on average 0-3 unconnected cases). However, 20 cases were reported in 2018, most of which were linked to an outbreak involving attendees of a multicultural dance in New Castle County; three cases (two confirmed and one probable) were reported in 2019. The Delaware Division of Public Health (DPH) is currently investigating an outbreak of mumps cases in New Castle County, Delaware. As of March 3, 2020, nine cases have been reported (seven confirmed, two probable), all in school-age children.

Recommendations

Providers are strongly urged to:

• Consider mumps when evaluating any patient with acute parotitis or other salivary gland swelling or orchitis
• Inquire about possible exposure to mumps in patients presenting with fever, malaise, headache, anorexia, myalgia or non-specific respiratory symptoms.
• Obtain specimens for laboratory confirmation: buccal swab for PCR (ideally within three days but no greater than nine days after symptom onset) and blood for serology (IgM and IgG) four or more days after symptom onset. (Note that in vaccinated individuals the IgM may remain negative).
• Suspect mumps patients must remain home and away from public spaces such as school and work for five days after parotitis onset or, in its absence, until the resolution of constitutional symptoms.
• Promptly report suspected (without waiting for laboratory confirmation), and confirmed cases to DPH Office of Infectious Disease Epidemiology (OIDE) at 302-744-4990 (normal business hours) or 1-888-295-5156 (outside of normal business hours), fax to 302-223-1540, or email to reportdisease@state.de.us. Pertussis is a reportable disease in Delaware.
• Consult DPH OIDE with any questions about a potential mumps case.
• Ensure that all clinic staff who have contact with patients have immunity to mumps (two documented doses of MMR or serologic evidence of immunity).

Laboratory testing:

Buccal swabs and serum serologies for both IgM and IgG are the available options to diagnose mumps. Buccal swabs are the preferred test as serology may not differentiate recent mumps exposure or previous vaccinations.

• If it has been ≤ 3 days since symptom onset, collect a buccal swab only for detection of viral RNA.
• If it has been > 3 days since symptom onset, collect a buccal swab and a serum sample for IGM detection.
• If the patient has orchitis/oophoritis, mastitis, pancreatitis, hearing loss, meningitis, or encephalitis, collect a buccal specimen for detection of viral RNA, a urine specimen for detection of viral RNA and a serum specimen for IgM detection, regardless of number of days since symptom onset.

Additional Information

Mumps is a viral illness acquired through respiratory droplets. The incubation period ranges from 12-25 days. The prodromal symptoms are nonspecific, and include myalgia, anorexia, malaise, headache, and low-grade fever. Parotitis is the most common manifestation. Contagiousness is similar to that of influenza and infected individuals are most contagious in the few days prior to and after parotitis. Transmission also likely occurs from persons with asymptomatic infections and from persons with prodromal symptoms. The most common complication in the post-vaccine era is orchitis. Less common side effects include mastitis, oophoritis, pancreatitis, deafness, meningitis, and encephalitis.

A person with two doses of MMR vaccine has about an 88% reduction in risk for mumps; a person with one dose has a 78% reduction in risk for mumps. In addition, disease symptoms are milder and complications are less frequent in vaccinated people. Also, high vaccination coverage helps to limit the size, duration, and spread of mumps outbreaks. Indications as listed below:

• MMR one dose for preschool-age children 12 months of age and older and persons born during or after 1957 not at high risk of mumps exposure
• MMR two doses for school-age children and adults at high risk of mumps exposure (i.e., healthcare personnel, international travelers and students at post-high school educational institutions)

MMR vaccine is not recommended for use as post-exposure prophylaxis.

For more information, visit the CDC @ https://www.cdc.gov/mumps/index.html

Call the DPH OIDE at 302-744-4990 (normal business hours) or 1-888-295-5156 (after hours), or email to reportdisease@state.de.us.

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