Glossary
mRNA (messenger RNA)
A molecule that carries instructions from a cell’s DNA to the machinery that builds proteins.
An mRNA vaccine delivers instructions for one protein from a virus (for COVID-19, the spike protein). The cell builds that protein for a short time, and the immune system learns to recognise it. The mRNA does not enter the cell nucleus, where DNA is kept, and it breaks down after use.
Because mRNA is fragile, it has to be packaged for delivery. In the COVID-19 vaccines, that package is a lipid nanoparticle.
Related terms: lipid nanoparticle, nanomedicine