Before I start, try to keep this context in your head. The context is that if the globalists are able to institute their vaccine passports then the turn key totalitarian system is unstoppable, the entire world will be enslaved, and the rape, torture, and exploitation is permanent.
Now put yourself in Trumps shoes at the beginning of this pandemic. The public is still asleep, everyone is just scared of the scary china sniffles, so if the vaccine works were fucked. 99.999% of people arent going to stand on principle and fight against mandates if the vaccine works well and is harmless.
So how do we make sure the people fight tooth and nail against this globalist hellscape bearing down on them?
What if the vaccine was very dangerous? Yup, that might do it.
I believe that the technology wasn't ready and they screwed up. Maybe the technology will never be ready. They've been working on mRNA delivery systems for roughly 20 years and it has never been used until now. It has been suggested that there was malfeasance in making some batches more dangerous than others, but I'm not convinced. It could have been just poor quality control in the factories that were rushed to production. Obviously when that happens they would have to do their best to hide the disaster.
Vaccines have been difficult to control contaminants when they weren't rushed to market. Take for example the SV40 virus contaminating polio vaccines for years. It is estimated that 100 million people were unintentionally exposed to it.
https://pubmed.ncbi.nlm.nih.gov/15322523/
Trump forced them to rush the vaccines and they didn't do a very good job. I think he knew they would screw up. He attempted to create a vaccine investigation committee when he took office. He went as far as contacting Robert Kennedy Jr., then he had to back off of it. I assume he was pressured politically by some donor.