Since the first diagnosis of Middle East respiratory syndrome (MERS) caused by the MERS coronavirus (MERS-CoV) in the Kingdom of Saudi Arabia in 2012, sporadic cases and clusters have occurred throughout the country (1). During June-August, 2015, a large MERS outbreak occurred at King Abulaziz Medical City, a 1,200-bed tertiary-care hospital that includes a 150-bed emergency department that registers 250,000 visits per year.In late June 2015, approximately 3 months after the last previously recognized MERS case in the hospital, a man aged 67 years with multiple comorbidities (diabetes, hypertension, congestive heart failure, and a history of coronary artery bypass graft surgery) and a 10-day history of fever and cough was evaluated in the emergency department ( Figure). The patient had no identified exposure to camels. A nasopharyngeal swab from the patient tested positive for MERS-CoV by reverse transcription-polymerase chain reaction (RT-PCR) (2). The patient was admitted and died in the hospital after 31 days. Although this patient's hospitalization overlapped with the onset of subsequent hospital-associated MERS cases, no direct links between this first case and any of the subsequent cases were identified.Approximately 3 weeks after the first patient's admission, a second patient, a man aged 56 years, with multiple comorbidities (diabetes with hypothyroidism, coronary artery disease, and hypertension with a history of coronary artery bypass surgery) and a history of camel exposure was evaluated in the emergency department for fever, cough, and shortness of breath. His nasopharyngeal specimen tested positive for MERS-CoV by RT-PCR. Three additional cases of MERS were epidemiologically linked to this patient's illness during his first week of hospitalization, including infections in two health care workers from the emergency department. An outbreak investigation was conducted by the hospital's infection control program to identify risk factors for infection and to develop and implement control measures. A suspected MERS case was defined as the occurrence of respiratory symptoms in a person with or without documented exposure to a patient with confirmed or probable MERS infection, but without confirmation by laboratory test results. A probable case was the occurrence of respiratory symptoms in a person with history of exposure to a patient with confirmed or probable MERS infection, but with inconclusive laboratory results (such as positive results by PCR on only one of the two genomic targets). A confirmed case was a suspected or probable case that was subsequently confirmed by a positive RT-PCR test for MERS-CoV. Contacts of persons with confirmed and probable cases were screened and persons with suspected cases were tested.A total of 130 MERS cases were detected at King Abulaziz Medical City during late June-late August. Among these cases, 81 (62%) were confirmed and 49 (38%) were probable, including 43 (33%) cases in health care workers; 20 of these 43 cases (47%) occurred in emergency department health care...

A total 130 cases of Middle East respiratory syndrome coronavirus were identified during a large hospital outbreak in Saudi Arabia; 87 patients and 43 healthcare workers. The majority (80%) of transmission was healthcare-acquired (HAI) infection, with 4 generations of HAI transmission. The emergency department was the main location of exposure.

The study demonstrated salient evidence that proper institution of IPC measures during management of an outbreak of MERS could remarkably change the course of the outbreak.

Between 19 April and 23 June 2015, 52 laboratory-confirmed cases of Middle East RespiratorySyndrome due to coronavirus (MERS) were reported from Al-Ahssa region, eastern Saudi Arabia. The first seven cases occurred in one family; these were followed by 45 cases in three public hospitals. The objectives of this investigation were to describe the epidemiological characteristic of the cluster and identify potential risk factors and control measures to be instituted to prevent further occurrence of MERS. We obtained the medical records of all confirmed cases, interviewed the members of the affected household and reviewed the actions taken by the health authorities. All the cases were connected. The index case was a 62-year-old man with a history of close contact with dromedary camels; three of the seven infected family members and 18 people in hospitals died (case-fatality rate, 40.4%). The median incubation period was about 6 days. The cluster of cases appeared to be due to high exposure to MERS, delayed diagnosis, inadequate risk communication and inadequate compliance of hospital health workers and visitors with infection prevention and control measures.