Bio-Manguinhos/Fiocruz COVID-19 (mRNA) Vaccine Booster

This is a descriptive, open-label, multicenter, non-randomized, uncontrolled phase I clinical study to evaluate the safety, reactogenicity, and immunogenicity of the COVID-19 Vaccine (mRNA) - Bio-Manguinhos/Fiocruz at doses of 25 μg, 50 μg, and 100 μg in healthy adults aged 18 to 59 years. Each study cohort (25 μg, 50 μg, and 100 μg) will initially include a sentinel group of five participants, who will be included sequentially, one by one. This inclusion will allow for an initial integrated risk-benefit assessment, evaluating whether the data from the included participant maintain the risk within acceptable limits for progression.