https://news.yahoo.com/trump-dismisses-covid-19-booster-184022005.html
It sounds like Trump is now beginning to publicly cast some doubt on the vaccines. He's starting cautiously, by questioning the booster shots, but I suspect (hope) that he will be slowly ramping up the questioning and criticism going forward, from here on out.
That's too bad. This may be an area where he could get better advice.