Figure 1.

Mechanism comparison of conventional mRNA vaccines and self-amplifying mRNA (SAM) vaccines. Traditional mRNA-based vaccines typically encode the antigen of interest along with 5ʹ and 3ʹ untranslated regions (UTRs). In contrast, SAMs encompass not only the antigen but also the viral replication machinery, facilitating intracellular RNA amplification and enhancing protein production. After internalization and arrival in the cytosol, the mRNA is recognized by ribosomes, leading to its translation into proteins, which then undergo post-translational modifications to attain the correct folding and functionality.