In pre-licensing clinical trials, the most frequently reported side effect was injection site pain. Within seven days of receipt of MRESVIA, the most commonly reported systemic adverse events included fatigue, headache, nausea/vomiting, muscle & joint pain, and chills. Higher rates of intensely itchy hives (urticaria) were reported among MRESVIA vaccine recipients than those who received the placebo.
One clinical trial participant who received MRESVIA reported facial paralysis within four days of vaccination. Additional adverse events reported among clinical trial participants who received MRESVIA included dehydration, allergic rhinitis, polymyalgia rheumatica, dermatitis, cardiac arrythmias including atrial fibrillation, pericarditis, superficial vein thrombosis, thrombocytopenia, and death. There were 106 deaths reported among clinical trial participants who received the vaccine, and 125 deaths among those who received the placebo. None of the reported deaths were considered to be related to vaccination by clinical trial investigators.
