This isn't like being a test pilot in an experimental rocket. This is like buying a 2021 Honda Civic. Is it different from the 2020 Civic? Yes. Could there be some unforeseen malfunction? It's not impossible. But this is not a bold new world of experimentation. It's a vaccine, with a tried and true development process and that has already been administered to tens of thousands of people (likely tens of millions over close to 12 months before a shot gets to your arm).