Middle East Respiratory Syndrome Coronavirus Superspreading Event Involving 81 Persons, Korea 2015

Abstract

Since the first imported case of Middle East respiratory syndrome coronavirus (MERS-CoV) infection was reported on May 20, 2015 in Korea, there have been 186 laboratory-confirmed cases of MERS-CoV infection with 36 fatalities. Ninety-seven percent (181/186) of the cases had exposure to the health care facilities. We are reporting a superspreading event that transmitted MERS-CoV to 81 persons at a hospital emergency room (ER) during the Korean outbreak in 2015. The index case was a 35-yr-old man who had vigorous coughing while staying at the ER for 58 hr. As in severe acute respiratory syndrome outbreaks, superspreading events can cause a large outbreak of MERS in healthcare facilities with severe consequences. All healthcare facilities should establish and implement infection prevention and control measure as well as triage policies and procedures for early detection and isolation of suspected MERS-CoV cases.

Keywords: Coronavirus; Emergency Room; MERS; Prevention; Superspreading Event.

Fig. 1. Abnormalities on chest imaging of the patient. Shown are computed tomography scans of the chest of the patient, obtained on May 21, 2015 (A, B, and C). Pre-existing pneumonic consolidation in the left lung (A) and newly appearing ground glass nodules were observed (A, B, and C, red lines). (D) is chest radiograph of the patient on May 25, 2015. Faint infiltrates were shown in both lung fields. (E) and (F) are chest radiographs of the patient on May 27 and May 29, 2015 respectively, when the patient stayed at the emergency room. Multiple patchy, opacities became more prominent on both lungs on May 27, 2015 and 2 days later, the opacities became more confluent.

Fig. 2. Clinical course of the patient and the epidemic curve for the cases of Middle East respiratory syndrome coronavirus infections directly exposed to the patient. The patient had productive cough due to pneumonia in his left lung prior to the onset of MERS-CoV infection. New infiltrates on chest radiograph and dyspnea developed on May 25, 2015, and 5 days later respiratory failure developed (A). Of the cluster of 91 cases related to Hospital C, 81 had exposure to the patient at the emergency room. Among 81 cases, the date of symptoms onset was not available in four cases. The incubation period ranged from 2 to 16 days, with a median of 6 days (B). ^*The case had another exposure to a family member with MERS-CoV infection between 8 to 10 days prior to onset of symptom. GGO, ground glass opacity; CT, computed tomography; MERS-CoV, Middle East respiratory syndrome coronavirus; INF-α2a, interferon-alpha2a.