Clinical and Epidemiologic Characteristics of Spreaders of Middle East Respiratory Syndrome Coronavirus during the 2015 Outbreak in Korea

Kang, Chang Kyung; Song, Kyoung-Ho; Choe, Pyoeng Gyun; Park, Wan Beom; Bang, Ji Hwan; Kim, Eu Suk; Park, Sang Won; Kim, Hong Bin; Kim, Nam Joong; Cho, Sung-il; Lee, Jong-koo; Oh, Myoung-don

A spreader was defined as an index patient who was suspected of causing a secondary infection of MERS-CoV. Super-spreaders and usual-spreaders were defined as those who transmitted MERS-CoV to 6 or more and those who transmitted to fewer than 6 individuals, respectively. Nonisolated in-hospital days were defined as the sum of calendar days of the patient's hospital stay before being effectively isolated. Chest radiographs at presentation were analyzed and the number of abnormal lung zones, which were arbitrarily divided into 6 areas, was counted. For subgroup analyses, we censored cases with symptom onset after June 7 after which stricter infection control measures were implemented by the government, such as public disclosure of the names of affected hospitals, organizing rapid response teams, and applying stronger surveillance and isolation policies (12) . Healthcare workers were also censored in another subgroup analyses because many wore personal protective equipment, which could also confound the transmission risk.