Unfortunate, but true the UAC seems to be more of a problem to users than to malware.

I rather doubt it was just as a result of this topic that avast added this to the detections, they actually need a sample to be able to analyse and add to the virus definitions.

That however, is an ongoing task playing catch-up with new variants.

I would still suggest you follow essexboy’s instructions, at the very least the OTS one which will provide detailed information on your system to ensure all elements are gone, registry entries, etc.