Charles Pfizer, the founder of the company, moved from Germany to New York as a 24 year old and got rich making medicine to treat stomach worms, and it did indeed work as such, only, it was toxic and caused side effects like vision problems, sometimes blindness and death and was discontinued. He used the money to buy real estate in New York and his many children continued the business into new medicinal products.
Note: I have no conspiracy theory on COVID19. I do worry about rushing a product to market without enough time to test for side effects, efficacy and longer-term consequences. History is full of such.
There is a lot of research in the history of science on unintended consequences and on the assumption of command and control over nature. The fact is it is unchartered territory (barely charted at least), like using Vasco da Gama's map of his voyage to India to try and replicate the journey under different weather conditions and less than most accurate measements.
I counsel caution, and if you decide it's worth the risk (given the death rate by age, older people should consider the vaccine a risk worthwhile ASAP. I personally will wait a year or two and see the science on one vaccine versus another, then choose accordingly.