COVID-19 vaccine safety – NCBI – NIH
http://www.ncbi.nlm.nih.gov › pmc › articles › PMC7521561
18 Sept 2020 — It presents scientific evidence of potential pitfalls associated with eliminating critical phase II and III clinical trials, and concludes that there is no substitute currently available for long-term human clinical trials to ensure long-term human safety.
Some info if you go to this site