Clinical Presentation and Outcomes of Middle East Respiratory Syndrome in the Republic of Korea

Choi, Won Suk; Kang, Cheol-In; Kim, Yonjae; Choi, Jae-Phil; Joh, Joon Sung; Shin, Hyoung-Shik; Kim, Gayeon; Peck, Kyong Ran; Chung, Doo Ryeon; Kim, Hye Ok; Song, Sook Hee; Kim, Yang Ree; Sohn, Kyung Mok; Jung, Younghee; Bang, Ji Hwan; Kim, Nam Joong; Lee, Kkot Sil; Jeong, Hye Won; Rhee, Ji-Young; Kim, Eu Suk; Woo, Heungjeong; Oh, Won Sup; Huh, Kyungmin; Lee, Young Hyun; Song, Joon Young; Lee, Jacob; Lee, Chang-Seop; Kim, Baek-Nam; Choi, Young Hwa; Jeong, Su Jin; Lee, Jin-Soo; Yoon, Ji Hyun; Wi, Yu Mi; Joung, Mi Kyong; Park, Seong Yeon; Lee, Sun Hee; Jung, Sook-In; Kim, Shin-Woo; Lee, Jae Hoon; Lee, Hyuck; Ki, Hyun Kyun; Kim, Yeon-Sook

The clinical features of patients with MERS-CoV infection in the Republic of Korea were generally similar to those reported in Saudi Arabia [4, 5, 10] . Asymptomatic patients were rare in this outbreak, presumably because confirmatory MERS-CoV tests were performed only for symptomatic patients, although active surveillance of asymptomatic HCWs involved in patient care was conducted at one hospital. In a previous outbreak in Jeddah, 25.1% of laboratory-confirmed cases were reported to have been asymptomatic; however, a telephone survey revealed that about 80% of those who were reached by telephone had experienced at least one symptom [4] . The proportions of patients with underlying medical conditions such as diabetes (18.8%), chronic lung disease (10.2%), or chronic kidney disease (4.8%) were smaller in this study, which might explain why cases with complicating respiratory or renal failure were relatively uncommon in the outbreak in the Republic of Korea, compared to those reported in Saudi Arabia. The incidence of pneumonia (80.8%) in this outbreak is similar to that reported in Saudi Arabia, although the proportion of patients requiring mechanical ventilation was smaller (24.2% in the Republic of Korea vs. 56-78% in Saudi Arabia) [5, 9] . In addition to the reduced presence of comorbidities, many patients in this study were diagnosed relatively early because rRT-PCR tests for MERS-CoV were actively performed for those with an epidemiological linkage as soon as fever or respiratory symptoms occurred. This early diagnosis might have led to early treatment initiation and thus prevented disease progression to a severe status.