Why Symantec anti-virus laboratory is very slow?

Hello everybody,

I really like the last version of NIS (2010)  but I absolutely confused about Symantec anti virus laboratory: they are extremely sloooow.

The typical example: 2 (two) days ago I sent the sample to Symantec (I used 2 ways: from my NIS 2010 and from Symantec's web page). I have no response from symantec (except tracking number from web submission) and NIS has no detection for  the virus!

Why another AV companies need just 4-5 hours to update antivirus databases but Symantec spent already 2 days and I have nothing?