He did manage to get a whole lot of influential haters to state very publicly that they would never take a vax developed under his admin (which despite the release date, it was). Have to imagine this in itself planted a good amount of confusion and doubt in some of the asleep to at least consider NOT taking it (while later exposing the haters’ big hypocrisy as a bonus) versus running headstrong with the Biden narrative. Biden then mandates the Trump vax as Trump probably expected. A difficult hand to play given limited if no other better options at the time.