Trump is pretending now to be pro-vaccine, and owning it, claiming it, because he has more chance to motivate THE SHEEP to be wary of it doing that, than he does to lose reputation with anyone who works this out for themselves. Trump is offering himself up for sacrifice in a sense because he is willing to help attract criticism of the vaccine. Those who disagree with Trump's pretended position are against the vaccine will not take it and not be at risk from it for now. But those who might question the vaccine could be put-off if it meant "agreeing with Trump" so Trump cannot be antivax openly.
There is even the chance some will stay away just because he pretends to like it. Kamala even said - "If the vaccine has anything to do with Trump, I ain't taking it"
First, I am not taking it. Second he set up a backchannel to tell me "we are not going to take it". Third he wouldn't have even run in 16, if he wanted me dead, he could have just let Jeb have the nom, Hillary win, and we would all be in a total comms blackout and this website would not even exist.
Trump is saying two thing - one public one backchannel. Believe the backchannel and your own sense. Remember your training.
Your third point actually makes sense