Study evaluates acute and long-term adverse events following immunization with COVID-19 Moderna vaccine

In a recent study posted to the medRxiv* pre-print server, a team of researchers conducted a case-control study at a mass vaccination center in Japan to evaluate acute and long-term adverse events following immunization (AEFI) with coronavirus disease 2019 (COVID-19) Moderna vaccine. There were 3,014 incidences of AEFI in 2,913 Moderna vaccine recipients, of which 101 recipients showed AEFI twice, first at the time of receiving the first dose and next on receiving the second vaccine dose. Except for anaphylaxis, the incidence rate of AEFI at the first dose was significantly higher than at the time of the second dose. Among the 1,201,688 vaccine recipients, the incidence rate of IHSR was 266, ISRR was 2129, anaphylaxis was two, and vasovagal syncope was 72. Among the 611,238 vaccine recipients without AEFI, 1,208 recipients were selected as matched controls 1 for Cases 1 and 9,940 recipients as control 2 for Cases 2.