Was it the dems who booed Trump at his own rally ?
The 2020 Democratic skepticism was about possible political pressure to approve a vaccine before the election, it wasn't about vaccines themselves
Harris explicitly said she'd take it if Fauci and public health experts endorsed it
Once the vaccines approved, Dems went all in on vaccination and Trump didn't promote them (still took credit for it when he could) OTOH he spent a looot of time dissing health officials