This is how updates for virus and malware and spyware protection work:
A flagrant piece of code, with extreme luck, gets found before it damages a lot of systems. These companies rip apart the virus code to find exploits that are traceable within a system, and then have to compile into the scanner's search files the things it has to look for. Then, they give notice to the user that their pattern file should be updated.
In my experience with windows, and dont tell me this is like comparing apples to oranges, a program or virus that gets deeply into the system (I am relating this to an app with root or su access), cannot be taken care of by conventional scanners
I have always, and forever will, find antivirus programs totally useless until you find they are needed. How simple is it to defend against a virus attack on android?
Uninstall a bad app,
Restore to a nandroid backup,
Or at worst sbf the phone, making sure to wipe and reformat everything.
But i think it will be a long long time before a monster virus appears that seats itself so deeply into a phone that an sbf is needed.