The first cases began emerging in the area around May 9, and authorities sprang into action, gathering credit card records and cell phone data to track down who might have been in the area during that time.
More than 77,000 people have been found and tested, authorities said today.
Of the 215 confirmed cases, 95 patients contracted the virus from visiting nightclubs patronized by an infected person, said Jung Eun-kyeong, director of the South Korean Centers for Disease Control and Prevention (KCDC).
The other 120 infections were traced to members of the original nightclub cluster.
South Korea has recorded a total of 11,142 cases and 264 deaths, according to the KCDC.