In view of the expanding cluster of MERS cases in Korea, the ECDC has released an updated Rapid Risk Assessment, which provides updated figures, maps, and analysis of of the spread of the virus in Korea to date.
Of particular interest, the ECDC is now counting 10 tertiary cases out of the 40 they have documented. The full 9 page report an be downloaded as a PDF file from the link below.
Severe respiratory disease associated with Middle East respiratory syndrome coronavirus (MERS-CoV), 5 June 2015
On 20 May 2015, the Korea Centers for Disease Control and Prevention notified WHO of the first laboratory confirmed case of MERS-CoV infection in a 68-year-old man with recent travel history to the Middle East. According to WHO, the man had the following travel history: 18–29 April, Bahrain; 29–30 April, United Arab Emirates; 30 April to 1 May, Bahrain; 1–2 May, Saudi Arabia; 2 May, Bahrain; and 2–3 May, Qatar. The case arrived at Korea’s Incheon International airport via Qatar on 4 May and was asymptomatic on arrival. The patient has no history of exposure to camels or contacts with MERS-CoV patients, and he did not visit any healthcare facilities while travelling in the Middle East. Investigation of the source of infection is ongoing .
As of 5 June, this primary case has resulted in 30 secondary cases. All secondary cases were exposed to the primary case before he had been diagnosed with MERS-CoV and before appropriate infection prevention and control measures had been implemented. Of the 30 secondary cases:
- Thirteen were admitted in the same ward or had contact with the index case as patients;- Four healthcare workers provided care for him;- Thirteen were family contacts or visitors to patients admitted to the same ward or sharing the same room with the index case: the wife of the index case, and twelve visitors, one of whom travelled to China.
On 2–5 June the health authorities in South Korea reported ten additional cases with no history of contact with the index case but contact with two secondary cases. One of these cases was a healthcare worker.
Furthermore, the health authorities are reporting four fatal cases.
Onset dates range from 11 May for the index case, until 01 June for the most recent nosocomial cases where the onset date is indicated, according to the Korea Centers for Disease Control and Prevention.
Credit ECDC - Rapid Risk Assessment June 5th
Conclusions and options for response
The importation of a MERS-CoV case to South Korea is not an unexpected event. MERS-CoV cases with travel history to the Arabian Peninsula have been diagnosed outside of the Middle East in the past. Cases should also be expected in the future given the ongoing transmission in the region and frequent international travel to and from the region. On several occasions, notably in France, the United Kingdom and Iran, such importations have resulted in secondary transmission to patients, healthcare workers and visitors who have been in contact with the primary imported cases, as well as to close relatives of a case.
Although the MERS-CoV cluster in South Korea is the largest that has so far been observed outside of the Arabian Peninsula, the cluster remains limited to patients, visitors to patients and healthcare workers in a few healthcare facilities and close relatives of the cases. The outbreak does not represent an increased risk of infection for travellers or visitors to South Korea. However, patients who present with severe acute respiratory disease in the EU and have recently been in contact with healthcare services in South Korea should be considered for MERS-CoV assessment, similar to patients having been in contact with healthcare services in the Arabian Peninsula.
The fact that the index case in the South Korean cluster does not have a documented history of exposure to camels or healthcare settings in the Arabian Peninsula is cause for concern. Continuous vigorous efforts are required to determine the likely source of infection to ensure that other, undetected, transmission chains are not ongoing.
WHO has stated that there is currently no indication that the virus is behaving differently to how it has behaved in the past and that there is no indication of sustained transmission from person to person. However, further details of the virus characterisation in South Korea are pending.
ECDC’s assessment continues to be that the MERS-CoV outbreak poses a low risk to the EU. Because of the continued risk of case importation to Europe after exposure in the Middle East, international surveillance for MERSCoV cases among travellers remains essential. Moreover, rapid efforts to contain the nosocomial clusters in the affected countries are vital to prevent broader transmission patterns.
Although sustained human-to-human transmission is unlikely, secondary transmission to unprotected close contacts, especially in healthcare settings,remains possible, as now documented in South Korea. The vast majority of cases detected in the Middle East continue to be due to nosocomial exposures.
The importance of eliciting a travel history from patients with severe respiratory disease cannot be overemphasised. The immediate, systematic and strict implementation of infection prevention and control measures in the hospital setting are essential to interrupt transmission and prevent clusters of healthcare-associated infection. Furthermore, the challenges of detecting rare imported cases of respiratory infection early on highlight the need for adequate infection prevention and control measures for all patients showing symptoms of acute respiratory infection.
WHO recommends that probable and confirmed cases should be admitted to adequately-ventilated single rooms or airborne precaution rooms. Healthcare workers caring for probable or confirmed cases of MERS-CoV infection should use contact and droplet precautions (medical mask, eye protection – i.e. goggles or face shield – gown and gloves) in addition to standard precautions. Airborne precautions should be applied when performing aerosol generating procedures .