Are there severe adverse vaccine effects?

A reported 4,041,396 first doses of Moderna COVID-19 vaccine had been administered in the United States, and reports of 1,266 (0.03%) adverse events after receipt of Moderna COVID-19 vaccine were submitted to the Vaccine Adverse Event Reporting System (VAERS). Among these, 108 case reports were identified for further review as possible cases of a severe allergic reaction, including anaphylaxis. Based on the submitted VAERs report, the possibilities are very low.