For many years, anti-virus has been a major player in the control of exploits and infections. The truth is that things have dramatically changed and much of the junk that is infesting our computers is not really a virus at all.
It is considered nuisance Malware. Since this type of infection is not considered a traditional virus, most virus scanners will not catch it. It will pass through unnoticed and in most cases not even a full scan will detect it.
