Played this vidya for about 6 months or so a few years ago.
The game involves you being the virus, bacteria, prion, etc (different levels) and controlling your mutations in order to destroy humanity.
The factors you described are a close mirror to the strategy that wins the virus stage. Only requires a few other factors, the others being late but rapid mutation into horrific symptoms and the virus staying undetected as a problem for so long that the world does not timely develop a vaccine.
From the sound of it, this virus failed in that last category. As for the horrific symptoms, it doesn't sound like it's met that threshold, either.
Long view - humanity wins.