WHO gives a situation assessment of the MERS-CoV outbreak in Republic of Korea

The outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) in the Republic of Korea continues to evolve, says the World Health Organisation (WHO).

The outbreak is the largest reported outside of Saudi Arabia, where the disease first emerged in April 2012.

Korea’s index (first) case was confirmed on 20 May and notified to WHO the same day. The case occurred in a 68-year-old Korean national with a recent history of travel to four countries in the Middle East. He developed symptoms on 11 May and subsequently sought care at two out-patient clinics and two hospitals. As the patient provided no history of potential exposure to the virus, MERS-CoV was not suspected and the patient was not treated in isolation. Efforts are under way to gather more information about exposures during the patient’s travels in the Middle East.

To date, contact tracing has identified a total of 25 laboratory-confirmed cases, including the index case, health care workers caring for him, patients who were being cared for at the same clinics or hospitals, and family members and visitors. Though data are preliminary, exposure times that led to infection may have been as short as 5 minutes to a few hours. To date, two of these cases have been fatal.

Given the number of clinics and hospitals that cared for the index case, WHO has said that further cases can be expected.

Evidence is mounting that camels can transmit MERS-CoV to humans through close contact

The occurrence of such a large outbreak outside the Middle East is a new development, as is exportation of the disease to a third country. The Republic of Korea Ministry of Health has further reported that two recently confirmed cases represent a third generation of transmission – from the index case, to someone exposed to that case, to a third person with no direct exposure to the index case.

Consistent application of adequate measures for infection prevention and control has halted other large clusters of cases associated with health care facilities. WHO recommends that droplet precautions be added to standard measures when providing care to patients with symptoms of acute respiratory infections.

WHO does not currently advise special screening at points of entry nor does it currently recommend the application of any travel or trade restrictions.

MERS-CoV is a newly emerging disease that remains poorly understood. Much about the behaviour of the virus remains shrouded in scientific uncertainty, though evidence is mounting that camels can transmit the virus to humans through close contact. Typical symptoms include fever, cough and shortness of breath. Pneumonia is common, but not always present. Gastrointestinal symptoms, including diarrhoea, have also been reported. Approximately 36% of reported patients with MERS-CoV have died.

WHO is confident that investigations under way in Korea, including the sequencing of viruses and sharing of the findings, will contribute to further scientific understanding of this disease.