Infect Chemother.  2019 Sep;51(3):256-262. 10.3947/ic.2019.51.3.256.

Investigation of a Mumps Outbreak in a Dental Clinic at a University Hospital

• Lee JE
• Lee SO
• Kang JS
• Yi J
• Kim KH

• KMID: 2459041
• DOI: http://doi.org/10.3947/ic.2019.51.3.256

Abstract

BACKGROUND
The Korean Society of Infectious Diseases recommends non-mandatory vaccination of newly employed healthcare workers (HCWs) with 2 measles-mumps-rubella (MMR) vaccine doses. Here, we aimed to investigate the seroprevalence of mumps among HCWs exposed to index patients with mumps and the efficacy of MMR vaccination as postexposure prophylaxis (PEP) when a mumps outbreak was encountered among HCWs in a tertiary university hospital in Korea.
MATERIALS AND METHODS
Four HCWs were diagnosed with mumps over a 4-day period in January 2016. Three were working at a dental clinic and one visited the clinic on the day of symptoms onset of the first patient. We investigated all HCWs who either worked in that dental clinic, visited the clinic, or being within 1.5 meter of the patients with mumps without wearing surgical masks. Seventy HCWs were exposed to 4 HCWs with mumps. We interviewed all the exposed HCWs to investigate mumps infection and MMR vaccination history; they were all tested for mumps IgG.
RESULTS
Of the 70 exposed HCWs, 56 (80%) were females; the median age was 34 years (range 21-59 years) and 3 had a history of mumps infection. The vaccination status verification of mumps among the HCWs was unavailable. As for serologic testing, 54 (77.1%) were seropositive. Seropositivity rate for the mumps virus in males was significantly lower than that in females (50.0% vs. 83.9% respectively, P = 0.007). A lower seroprevalence of mumps was observed among HCWs aged ≥40 years than those aged <40 years; however, this difference was not significant (65.2% vs. 83.0%, P = 0.096). During the initial intervention, all exposed HCWs were vaccinated because the turnaround time for serologic testing was expected to be >2 days. Thirty-four (62.9%) of 54 seropositive HCWs and 16 seronegative HCWs were administered MMR vaccines as PEP and following this, no additional cases of mumps were encountered during the maximum incubation period.
CONCLUSION
Of the exposed HCWs, 77.1% were mumps-seropositive. Seropositive rates differed according to factors such as age and sex. Eligible HCWs received a MMR vaccine as PEP and no additional mumps cases occurred during the incubation period. It was useful in our infection control activities during the mumps outbreak.

Keyword

Mumps; Measles-mumps-rubella vaccine; Healthcare workers

MeSH Terms

Communicable Diseases
Delivery of Health Care
Dental Clinics*
Female
Humans
Immunoglobulin G
Infection Control
Korea
Male
Masks
Measles-Mumps-Rubella Vaccine
Mumps virus
Mumps*
Seroepidemiologic Studies
Serologic Tests
Vaccination
Vaccines
Immunoglobulin G
Measles-Mumps-Rubella Vaccine
Vaccines

Figure

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  Figure 1 The epidemic curve of 4 mumps cases encountered at Pusan National University Hospital (January 15–21, 2016). Three HCWs were working at the dental clinic with unknown exposure date and the fourth patient was the HCW who visited the dental clinic on the first day of the outbreak. HCW, healthcare worker; DC, dental clinic.

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