I googled "Johnson and Johnson vs Pfizer efficacy."
I ignored the first two ads.
Saw this:
https://www.cdc.gov/mmwr/volumes/70/wr/mm7038e1.htm
And there are a number of other articles mentioned in the search. If I were to go through them, I would focus on AMA articles, medical journals, etc. as a starting point.
edit- I got the pfizer last jan/feb, and booster here recently. No problems. Our office administered J&J vaccines last spring. No problems. Just a data point from a car parts website.
