The FDA approves a vaccine for use only if it is proven safe and effective, after clinical trials have been conducted with thousands of people, and when its benefits outweigh any risks. The COVID-19 vaccine builds on years of scientific research and an unprecedented level of scientific investment and cooperation. Every study and every phase of every trial was carefully reviewed and approved by a safety board and the FDA. The process was transparent and rigorous throughout, with continual oversight and expert approval. The Pfizer vaccine alone had a trial of over 40,000 people over a period of many months without any serious incidents.

Since vaccines became available in December, millions of people across the country have received the vaccine with a relatively small number of reports of serious adverse reactions.