Currently, at least 122 people have been infected with MERS in South Korea, all from a single index case who became sick in mid-May. The index case had visited several health care facilities before being diagnosed and hospitalized. Several health care workers became infected while examining this individual prior to hospitalization. The index case exposed a number of people to the MERS coronavirus during his hospitalization. Several of these exposed individuals were released from the hospital and later became symptomatic and were later diagnosed with MERS. By that time, some these individuals had infected others and the chain of transmission began.
An important component of breaking the transmission chain and containing an infectious disease outbreak is restricting its geographic spread. As of June, 11, 2015, South Korean health authorities have identified 38 hospitals where MERS patients are currently being treated or where MERS patients apparently visited prior to being diagnosed. The map below shows the wide geographic distribution of these hospitals across South Korea. We will have to wait for the MERS incubation period to pass to see whether or not MERS cases start to occur in these outlying areas.
Data from: http://cdc.go.kr/CDC/cms/cmsFileDownload.jsp?fid=5767&cid=63408&fieldName=attach1&index=1