Again, replying here rather than politics,
When I read this, I assumed you were right and Trump’s claims were just his typical, optimistic exaggeration (or lies, if you prefer) on the virus / vaccine rollout. But actually, that was what PFE was saying in October before the election… delays. Here’s their CEO promising just that
https://www.pfizer.com/news/hot-topics/moving_at_the_speed_of_science
in March, I declared a bold ambition: that Pfizer would create a vaccine, and we would devote any and all resources necessary to be successful. I further announced, after consulting with our scientists, that we could have vaccine data ready to submit to the FDA by end of the third quarter, in October, and hopefully a hundred million doses delivered by the end of the year. I knew our goal was ambitious, but it would also be critical to protect against the second wave of cases that could accompany the return of colder weather in the Fall.
So I’m sure Trump just heard these optimistic estimates from the vaccine companies and repeated them.