The Moderna COVID-19 vaccine’s local reactions, systemic reactions, adverse events, and serious adverse events
Publication year: 2022
Local reactions were reported by the majority of vaccine recipients and at higher rates than placebo recipients. Vaccine recipients reported higher rates of local reactions after dose 2 than dose 1. The frequency of local reactions was higher in the older age group (ages 2 to 5 years) than the younger age group (ages 6-23 months) (73.4% vs 54.4% after dose 2). Pain at the injection site was the most frequent and severe reported solicited local reaction among vaccine recipients. After dose 1, the older age group reported pain more frequently than the younger age group (61.4% vs 37.4%); a similar pattern was observed after dose 2 (71.4% vs 46.2%). Axillary (or groin) swelling or tenderness was the second most frequently reported local reaction. Axillary (or groin) swelling or tenderness was reported slightly more frequently in the younger age group than the older age group (9.3% vs 9.1% after dose 2). Injection site redness and swelling following either dose were reported less frequently. Redness and swelling were more common after dose 2. No grade 4 local reactions were reported. Overall, the median onset of local reactions in the vaccine group was 1 day after either dose, with a median duration of 2 days.