Moderna’s mRNA-1273 vaccine safety and immunogenicity assessment were evaluated in clinical trials that included 30,400 volunteers of different ages, races and ethnicities. 82% were at risk of occupational exposure and 22.3% had at least one high-risk factor.
Efficacy observed 14 days after administration of the second dose suggested that it can prevent illness in 94.1% of the adults vaccinated and 86.4% of the over 65 years of age adults with or without comorbidities. Efficacy observed in people with any comorbidity and any age group was 90.9%.
Most of the adverse effects detected were mild or moderate, disappeared a few days after receiving the vaccine and were not different to others described for the most common vaccines (including severe allergic reactions). The most frequently reported in clinical trials was pain at the site of injection, which may appear on the first 7 days postvaccination and resolve in a few days. Other adverse effects reported in the first 7 days after administration of the first and second dose were: sweating, erythema and increased sensibility on the vaccinated arm, fatigue, headache, muscular pain, cramps, joint pain, fever, nausea and vomiting.
Most common adverse reactions associated with Moderna’s mRNA-1273 vaccine:
- are mild or moderate
- disappear within a few days