Control of an Outbreak of Middle East Respiratory Syndrome in a Tertiary Hospital in Korea.

<bold>Background: </bold>In 2015, a large outbreak of Middle East respiratory syndrome (MERS) occurred in the Republic of Korea. Half of the cases were associated with a tertiary care university hospital.<bold>Objective: </bold>To document the outbreak and successful control measures.<bold>Design: </bold>Descriptive study.<bold>Setting: </bold>A 1950-bed tertiary care university hospital.<bold>Patients: </bold>92 patients with laboratory-confirmed MERS and 9793 exposed persons.<bold>Measurements: </bold>Description of the outbreak, including a timeline, and evaluation of the effectiveness of the control measures.<bold>Results: </bold>During the outbreak, 92 laboratory-confirmed MERS cases were associated with a large tertiary care hospital, 82 of which originated from unprotected exposure to 1 secondary patient. Contact tracing and monitoring exposed patients and assigned health care workers were at the core of the control measures in the outbreak. Nontargeted screening measures, including body temperature screening among employees and visitors at hospital gates, monitoring patients for MERS-related symptoms, chest radiographic screening, and employee symptom monitoring, did not detect additional patients with MERS without existing transmission links. All in-hospital transmissions originated from 3 patients with MERS who also had pneumonia and productive cough.<bold>Limitations: </bold>This was a retrospective single-center study. Statistical analysis could not be done. Because this MERS outbreak originated from a superspreader, effective control measures could differ in endemic areas or in other settings.<bold>Conclusion: </bold>Control strategies for MERS outbreaks should focus on tracing contacts of persons with epidemiologic links. Adjusting levels of quarantine and personal protective equipment according to the assumed infectivity of each patient with MERS may be appropriate.<bold>Primary Funding Source: </bold>Samsung Biomedical Research Institute. [ABSTRACT FROM AUTHOR]