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.
Yeah he actually said it over the phone during an interview with Sean Hannity. I can’t find the sound bite, but here is the article published on 4/23/21. It’s about halfway down the article:
https://www.deseret.com/2021/4/23/22399234/former-president-donald-trump-americans-coronavirus-vaccine-obama-bush-clinton-carter
Edit: here’s the video, time stamp 3:30:
https://nypost.com/2021/04/19/trumps-urges-americans-to-get-vaccines-takes-shot-at-jj-pause/
Thank you!