How many people have had adverse reactions to the Pfizer mRNA vaccine since 2019?

It is difficult to estimate the exact number of people who have had adverse reactions to the Pfizer mRNA vaccine since 2019, as not all reactions are reported. According to the U.S. Centers for Disease Control and Prevention (CDC), as of April 6, 2021, at least 35 million doses of the Pfizer-BioNTech COVID-19 vaccine were administered in the United States. As of April 6, 2021, a total of 7,945 reports of anaphylaxis and 43,247 total vaccine Adverse Events (AEs) associated with the Pfizer-BioNTech vaccine were reported to the Vaccine Adverse Event Reporting System (VAERS).