Overview
- The concept of mRNA as a vaccine platform has evolved over several decades, using host cells to produce antigens.
- mRNA vaccines can induce both B cell and T cell immune responses and avoid unwanted vector-related antigens that may interfere with booster doses.
- Unmodified mRNA (uRNA) may be highly reactogenic, while modified mRNA improves tolerability, purity, and potency.
- Self-amplifying mRNA (saRNA) enables higher antigen expression but may reduce stability due to larger construct size.
- mRNA vaccines require delivery systems such as lipid nanoparticles (LNP) to enable efficient entry into cells.
- During the COVID-19 pandemic, mRNA vaccines were developed in under one year from genetic sequencing to licensure.
- Widely used products include BNT162b2 (Pfizer/BioNTech) and mRNA-1273 (Moderna), which show differences in CD8 T cell response in vitro.
- Both licensed modified mRNA vaccines demonstrate acceptable safety profiles and high efficacy (≥94%) in large clinical trials.
- Vaccine efficacy against symptomatic disease exceeded 90% during the first six months of follow-up.
By Global Health Press
