Not all AV's detect all viruses. Some AV's don't add certain new definitions for months or many after some other AV's. Strange to see free AV's updating definitions for new 'known' viruses well before the commercial ones. lol So no 'one' AV is guaranteed. All miss or are slow to find certain ones in their updates, due to their own lapse in research.

If LW was to add an AV, then lawsuits would be filed for damage done with the user's thoughts that their system was safe (false sense of security) when they willy nilly download viruses themselves without doing any research ... such as here Virus thread: Typical virus spam file sizes - Make a note of them (click on blue link to see)