Only 51% of anti-virus scanners detect zero-day malware | Myce.com
VirusTotal uses dozens of virus scanners which scan uploaded files. The 
website is mainly intended to be a second opinion and is according to 
the developers not usable for testing and rating anti-virus software. 
VirusTotal uses the command line version of virus scanners which can 
differ from the desktop version used by most consumers.