Not true. It all depends on the virus. A service might start up in the background that allows remote access via a particular port for example. It may not get used for an arbitrary amount of time, but that doesn't mean the service hasn't started running almost immediately.
In my wandering...
Hello,
I'm Smoe, i'm new here. Found this place whilst looking for the masamune devastator, but found many other cool things here. Looks like a cool hobby. Hopefully my son and I can make some of these as he gets older.