Essentially, everyone relies on governmental regulatory agencies to ensure these vaccines are in fact, safe and appropriate.
True, but this is true for all drugs sold legally in the USA. Results of clinical trials are published in the scientific literature and are available on pubmed if you want them. (Charlie can probably tell you where to find them if you want more details)
And profit margins are lower on vaccines than on many other products that these companies make. That does not mean that they make them at a loss, nor should they, but it does mean that they can and do make more on other things.