Sex: U
Vaccine: MU
Symptoms: Mumps antibody test negative, Parotid gland enlargement, Parotitis
Clinical narrative: Information has been received from authors of a published article. MATERIALS AND METHODS Mumps was a reportable disease in this region. The outbreak case definition was acute parotitis or other salivary gland swelling, orchitis, or oophoritis in a person who had an epidemiologic link to the affected university between 12-JAN-2014 and 25-MAY-2014. Patients were classified as a confirmed case if they had positive laboratory confirmation either with mumps reverse-transcription polymerase chain reaction (RT-PCR) testing or viral culture, or as a probable case if they had a positive serologic test for mumps immunoglobulin M (IgM) or an epidemiologic link to the outbreak. At the Public Health Laboratory (PHL), serum specimens were tested for mumps-specific IgM antibodies using enzyme-linked immunosorbent assay (Serion, catalogue number ESR103M). Specimens with indeterminate IgM results were considered IgM negative for the purpose of the analysis. RT-PCR was performed at the PHL. RNA was extracted from buccal swab specimens using the NucliSens easy MAG automated extraction system (bioMerieux). Mumps virus RNA was detected using a realtime RT-PCR assay targeting the nucleoprotein (N) gene. RESULTS On unknown dates, the patients vaccinated a dose of Mumps Virus Vaccine Live (manufacturer unknown)(dose, route, lot# and expiration date were unknown). A total of 56 cases were identified during the outbreak investigation with onset from 12-JAN-2014 and 30-APR- 2014. Three additional cases linked to the outbreak resided outside of the region and were excluded from the analyses. The index case was a student who developed unilateral parotid swelling on 12-JAN-2014. The student was seen at the health center, and mumps serologic testing was performed; however, the provider ruled out a mumps diagnosis given the negative IgM result. RT-PCR testing was not performed. The index case exposed another student who subsequently presented to the student health center with symptoms consistent with mumps on 31-JAN- 2014; the student was diagnosed with sialoadenitis, and diagnostic testing for mumps was not performed. On 19-FEB-2014, the student health center reported 5 students with parotitis to the DOHMH, including the index case and 4 students who presented to student health for evaluation on 18-FEB-2014. Of the 56 total cases, 28 (50%) cases were classified as confirmed and 28 (50%) were classified as probable cases. Among all cases, 53 (95%) were students, 1 (2%) case was a staff member, and 2 (4%) cases had other epidemiologic links to the facility. The median age of cases was 20 years (range 18-37 years). Twenty-six (46%) cases were female. All cases had parotitis and 2 male cases (7%) had orchitis. Three (5%) cases were hospitalized. Fifty-four (96%) cases had documentation of at least 1 Mumps Virus Vaccine Live(manufacturer unknown) including 32 (57%) cases with 2 documented doses. One (2%) case was unvaccinated due to religious exemption, and the vaccination status of 1 (2%) nonstudent case was unknown. Of the 56 cases, 52 (93%) had laboratory testing performed. Of the 40 cases who had RT-PCR testing performed, 27 (68%) tested positive; of the 44 cases who had mumps IgM serologic testing performed, 2 (5%) tested positive. Mumps virus was isolated from 2 of 11 (18%) cases tested by viral culture. When comparing specimens collected <2 days vsï¼2 days after parotitis onset, 83% vs 44%, respectively, of specimens tested for RT-PCR were positive (P = .015). Mumps outbreaks can occur in highly vaccinated populations. Mumps should be considered in patients with parotitis regardless of vaccination status. The outcome of the events was unknown. The reporter considered the events to be related to the Mumps Virus Vaccine Live (manufacturer unknown). Additional information has been requested.