The best information I have:
NO Anti-Malware(Virus) program is 100% All of them miss something.
Thankfully most miss different things so if you run more than one you are far less likely to have issues.
The recommendation is to use at least 3
And do not count "Microsoft Security Essentials" as it is not all that good.
AVG, AVAST, Malware Bytes,, Hitman all good
Norton I am told is honest
McAffee.. Well many of us know the man is wanted on warrants, if that is they hae not been satisfied but that has nothing to do with computer crimes.
But back when he (And Norton) first came out with Anti Virus programs I wondered if they were perhaps seeding the market.
My Source says Norton would never thik of such a thing..
He also gave me the "Day Job" title and location of the McAffee employe so hired.