The manufacturing process, often in eggs or large bioreactors, is laborious and time intensive. Successful shots typically take more than a decade to develop, according to a 2013 study published in the journal PLOSOne.

Messenger RNA promises to cut that time by taking advantage of the body’s own molecular machinery, essentially teaching cells how to make a protein similar to one found on the virus, which then triggers the body’s immune response…

With mRNA, vaccine development becomes an engineering issue, rather than a scientific challenge. Companies can design mRNA vaccines relatively quickly once they know the genetic sequence of the pathogen. Researchers use the genetic sequence of a targeted virus to program the mRNA that can fight it.

In the journal Nature Reviews Immunology last November, the National Institute of Allergy and Infectious Diseases’ Anthony Fauci and John Mascola wrote, “MRNA has the potential to be a rapid and flexible vaccine platform. Starting from gene sequence, mRNA vaccines can be produced in a few weeks.”