BACKGROUND: In February 2016, the Cambridge Public Health Department (CPHD) received notification of two confirmed cases of mumps in students at a local university. In collaboration with the Massachusetts Department of Public Health (MDPH) and the university, CPHD facilitated suspect case investigation, contact tracing, and risk communication.
METHODS: Suspect cases were placed into isolation for five days following the onset of parotid swelling. Vaccination status was obtained through the university's health record. CPHD staff followed up with suspect cases by email and phone to investigate exposure patterns and identify close contacts during the infectious period. CPHD provided close contacts with educational information, verified their vaccination status, and ensured they were monitoring themselves for mumps symptoms for the duration of their potential incubation period. Unvaccinated or undervaccinated close contacts were encouraged to begin the vaccination series or be quarantined starting 12 days after the suspect case's first infectious day through 25 days after the suspect case's last infectious day. Standard operating procedures from the university were written in consultation with MDPH and CPHD so that all university medical and administrative personnel followed the same diagnosis, specimen collection, and isolation protocols. Regulatory authority granted by the Code of Massachusetts Regulations assisted CPHD in enforcing isolation and quarantine requirements as well as conducting necessarily surveillance.
RESULTS: The university's undergraduate and graduate populations had vaccination rates between 98-99%. Despite this, throughout 2016, CPHD received notification of and attempted to interview more than 150 suspect cases, almost all of whom were fully vaccinated, and follow up with more than 200 close contacts. Many suspect cases were members of athletic teams, social clubs, and other extracurricular activities. CPHD coordinated with coaches and club leaders to provide educational information to a wider audience. Due to the unique characteristics of college students, CPHD had higher success reaching individuals through email rather than over the phone. CPHD's efforts in enforcing isolation and quarantine requirements and in encouraging vaccination were supported by university staff. Despite two peaks, the outbreak subsided after the semester ended and many students left campus.
CONCLUSIONS: Although mumps is a vaccine-preventable disease and the university had high vaccination coverage, the close living conditions and highly social nature of college students facilitated the virus' spread. However, with clear protocols in place and a thorough understanding of students' communication preferences, case investigation can be conducted and isolation and quarantine protocols can be enforced with greater ease and efficiency.