Government, health organizations such as CDC & WHO and "authoritative" news sources.

They may want to promote the vaccines because they are good, and they want the pandemic to be over right?* The question is whether they are doing it honestly or not. I think not. They decided that there is a conclusion that they want people to reach, and they are willing to go as far as obstructing facts to make you reach that.

* they may have additional reasons related to conflicts of interest, corruption, etc.