MERS in South Korea and China: a potential outbreak threat?
Authors: Shuo Su, Gary Wong, Yingxia Liu, George F Gao, Shoujun Li, Yuhai Bi
Journal: The Lancet (2015)

First reported in September, 2012, human infections with Middle East respiratory syndrome coronavirus (MERS-CoV) can result in severe respiratory disease, characterised by life-threatening pneumonia and renal failure.1Al-Tawfiq JA Hinedi K Ghandour J et al.Middle East respiratory syndrome coronavirus: a case-control study of hospitalized patients.Clin Infect Dis. 2014; 59: 160-165Crossref PubMed Scopus (197) Google Scholar Countries with primary infections of MERS-CoV are located in the Middle East, but cases have been occasionally exported in other countries (figure). Human-to-human infections of MERS-CoV are rare2Chan JF Lau SK To KK Cheng VC Woo PC Yuen KY Middle East respiratory syndrome coronavirus: another zoonotic betacoronavirus causing SARS-like disease.Clin Microbiol Rev. 2015; 28: 465-522Crossref PubMed Scopus (672) Google Scholar and confirmed cases are usually traced back to contact with camels, an intermediate host species for MERS-CoV.3Azhar EI El-Kafrawy SA Farraj SA et al.Evidence for camel-to-human transmission of MERS coronavirus.N Engl J Med. 2014; 370: 2499-2505Crossref PubMed Scopus (664) Google Scholar As of May 24, 2015, worldwide, a total of 1134 cases and 427 deaths (case fatality rate 37·7%) have been reported, according to WHO.4WHOGlobal Alert and Response. Middle East respiratory syndrome coronavirus (MERS-CoV)—Republic of Korea.http://www.who.int/csr/don/24-may-2015-mers-korea/en/Date: May 24, 2015Google Scholar There is no approved vaccine or treatment. On May 11, 2015, a 68-year-old male in South Korea developed symptoms and sought medical care at a clinic between May 12–15, before admittance into hospital on May 15.4WHOGlobal Alert and Response. Middle East respiratory syndrome coronavirus (MERS-CoV)—Republic of Korea.http://www.who.int/csr/don/24-may-2015-mers-korea/en/Date: May 24, 2015Google Scholar The patient had been travelling between April 18–May 3 through Bahrain, the United Arab Emirates, Saudi Arabia, and Qatar. He was asymptomatic upon return to South Korea on May 4, but tested positive for MERS-CoV on May 20, along with two additional cases: his 64-year-old wife, and a 76-year-old male who was a fellow patient.4WHOGlobal Alert and Response. Middle East respiratory syndrome coronavirus (MERS-CoV)—Republic of Korea.http://www.who.int/csr/don/24-may-2015-mers-korea/en/Date: May 24, 2015Google Scholar Concerns of further MERS-CoV spread were confirmed when a 71-year-old male fellow patient, the daughter of the 76-year-old case, and two medical staff developed symptoms and were diagnosed with MERS-CoV infection (appendix). As of May 29, 2015, South Korea has 12 laboratory-confirmed cases of MERS-CoV, and more than 120 additional contacts under surveillance.5International Society for Infectious DiseasesMERS-COV (50): South Korea, China, Saudi Arabia.http://www.promedmail.org/direct.php?id=3395374Google Scholar On May 28, a 44-year-old male traveller from South Korea to Huizhou, China was admitted into hospital. MERS-CoV infection was confirmed on May 29, marking the first laboratory-confirmed case in China (appendix), and the patient was immediately put in isolation. This patient was the son of the 76-year-old South Korean patient. He had visited his father in the hospital on May 16, developed symptoms on May 21,6WHOGlobal Alert and Response (GAR). Middle East respiratory syndrome coronavirus (MERS-CoV)—China.www.who.int/csr/don/30-may-2015-mers-china/en/Date: May 30, 2015Google Scholar and travelled to Hong Kong by plane on May 26 before arriving by road into mainland China via Shenzhen.6WHOGlobal Alert and Response (GAR). Middle East respiratory syndrome coronavirus (MERS-CoV)—China.www.who.int/csr/don/30-may-2015-mers-china/en/Date: May 30, 2015Google Scholar In response, the Chinese health authorities promptly placed 38 high-risk contacts under surveillance, but it is not known whether additional contacts exist and further MERS-CoV infections in China remains a possibility. This series of events highlighted issues with the current surveillance system put in place to prevent the importation of infectious diseases. The diagnosis for MERS-CoV infection was made on May 20 for the 76-year-old patient. His 44-year-old son should have been monitored as a close contact of the laboratory-confirmed case, with provisional quarantine and testing upon development of symptoms and isolation upon a positive diagnosis. Such a high-risk case should not be travelling until after the incubation period, which is between 2–15 days for MERS-CoV.2Chan JF Lau SK To KK Cheng VC Woo PC Yuen KY Middle East respiratory syndrome coronavirus: another zoonotic betacoronavirus causing SARS-like disease.Clin Microbiol Rev. 2015; 28: 465-522Crossref PubMed Scopus (672) Google Scholar Non-compliance by the patient regarding travel advice likely contributed to this scenario.5International Society for Infectious DiseasesMERS-COV (50): South Korea, China, Saudi Arabia.http://www.promedmail.org/direct.php?id=3395374Google Scholar These events serve as a timely reminder that natural geographical barriers against pathogens can now be easily overcome through trade and travel, and marks the first MERS-CoV import case that did not come directly from the Middle East. These developments are worrisome given that Hong Kong airport is a major international transport hub, and thus any potential infections can travel worldwide in a short time. After dealing with several pandemic threats over the past 15 years, notably severe acute respiratory syndrome coronavirus (SARS-CoV) in 2003, H1N1 influenza in 2009, and Ebola virus in 2014–15, authorities now have ample experience in outbreak response compared with past years. In addition to the need for increased vigilance from health authorities, compliance by the public is crucial for the effective implementation of outbreak responses. Everyone is responsible for upholding the principles of public health, and must play their part to minimise the chances of disease transmission across borders. We declare no competing interests. Download .pdf (.52 MB) Help with pdf files Supplementary appendix MERS—the latest threat to global health securityThe spread of Middle East respiratory syndrome (MERS) to South Korea, and now to China, is an important signal of the need for increased vigilance in global health security measures. As reported in Correspondence in this week's issue, the rapid transmission of MERS in South Korea led to 12 laboratory-confirmed cases over a 2-week period in May, and many more cases since, with relatives, medical staff, and a fellow patient all contracting the disease, which started with one 68-year-old man who had travelled to the Middle East. Full-Text PDF