I have no problem stating publicly my feelings on that vaccine. In clinical trials, the mRNA vaccines were shown to be 80%-90% effective, while the J&J vaccine was around 60%. Now any one of these vaccines would give the recipient antibodies, it's just that Pfizer and Moderna are more effective. Turns out they have fewer side effects. No one knew at the time that J&J could possibly cause lethal blood clots, especially in women of a certain age. But my friend Sue got the J&J shot and she was violently ill for over 5 days. She had fever, chills, sore throat, and digestive issues at both ends. She said she hurt so bad that even her teeth hurt.
I had also studied about mRNA technology in pathophysiology class while I was in school getting my medical transcriptionist training, so I was super excited about the potential of that vaccine, plus the way it works, all they have to do is tweak a few codes to combat mutations. Viruses mutate and it will take time for new vaccines using other technology. The mRNA technology is far superior, IMO. And turns out fewer side effects.