You may have noticed that the Symantec Endpoint Protection (SEP) definitions are dated 12/31/09 and appear not to be updated. This is due to a bug in the SEP software. Symantec is currently working on a solution for it right now. Although the pattern date remains at 12/31/09, take a look at the revision number. Revision 119 means you have the pattern current with the 1/7/10 definitions even though the pattern is displayed as 12/31/09. Here’s a link to a Symantec Document explaining the situation http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2010010308571348. If the revisions keep increasing then the patterns are getting updated.
*** Update. As of 1/18/10 it appears that this issue has been resolved. Virus patterns now appear with the correct date.