According to SciFi Japan, we can look forward to another Host in the near future.
The site, reporting from a press release from Chungeorahm Film, which is the Japanese prodco that put out The Host, the new Host film is actually a prequel to the original film, filling in plot details of the first film's prologue and will also contain much more monster mayhem.
The plot revolves around the restoration of the Cheonggyecheon, a stream that runs through the heart of Seoul and into the Han River. For years the stream was covered by concrete, but it was restored in 2005. It is now one of the main tourist attractions in Seoul, although the restoration has made life more difficult for the inhabitants around the stream. This prequel will take place in 2003, when the restoration just started, and it seems that the unearthing of this stream gives way to the monsters getting out.
The script was written by comic artist Kang Full, although a director and cast have yet to be chosen.