Middle East respiratory syndrome: what we learned from the 2015 outbreak in the Republic of Korea

Abstract

Middle East Respiratory Syndrome coronavirus (MERS-CoV) was first isolated from a patient with severe pneumonia in 2012. The 2015 Korea outbreak of MERSCoV involved 186 cases, including 38 fatalities. A total of 83% of transmission events were due to five superspreaders, and 44% of the 186 MERS cases were the patients who had been exposed in nosocomial transmission at 16 hospitals. The epidemic lasted for 2 months and the government quarantined 16,993 individuals for 14 days to control the outbreak. This outbreak provides a unique opportunity to fill the gap in our knowledge of MERS-CoV infection. Therefore, in this paper, we review the literature on epidemiology, virology, clinical features, and prevention of MERS-CoV, which were acquired from the 2015 Korea outbreak of MERSCoV.

Keywords: Coronavirus; Coronavirus infections; Disease outbreaks; Korea; Middle East respiratory syndrome coronavirus.

Figure 1.

Confirmed global cases of Middle East respiratory syndrome coronavirus reported to World Health Organization (WHO) as of November 17, 2017 (n = 2,103). Other countries: Algeria, Austria, Bahrain, China, Egypt, France, Germany, Greece, Iran, Italy, Jordan, Kuwait, Lebanon, Malaysia, the Netherlands, Oman, Philippines, Qatar, Thailand, Tunisia, Turkey, United Arab Emirates, United Kingdom, United States of America, Yemen. Adapted from World Health Organization [2].

Figure 2.

Epidemiological curve for the 2015 Middle East respiratory syndrome coronavirus (MERS-CoV) outbreak in the Republic of Korea. (A) Overall epidemiologic curve by date of symptom onset. Red color denotes the index patient. (B) Epidemic curves for each of the three main clusters. Outbreaks at Hospital C, Hospital H, and Hospital M and N are depicted in yellow, green, and purple color, respectively. Adapted from Korea Centers for Disease Control and Prevention [7].

Figure 3.

Progression of Middle East respiratory syndrome (MERS) pneumonia. (A) Severe cases. (B) Mild cases. In severe cases, pneumonia progressed suddenly around 7 days after symptom onset. Adapted from Oh et al., with permission from Massachusetts Medical Society [50].

Figure 4.

Case fatality ratio of Middle East respiratory syndrome during the 2015 Korea outbreak. Case fatality ratio was 10.1% (11/109) in patients without underlying diseases (A), and 35.1% (27/77) with underlying diseases (B). Overall case fatality ratio was 20.4% (38/186).