A vaccine comprising solely of messenger RNA protects animals against influenza infection, reports a study published online this week in Nature Biotechnology. If this approach proves effective in humans, it might allow flu vaccines to be designed and manufactured in weeks rather than months, making responses to pandemics much faster.
Existing influenza vaccines are produced in chicken eggs or cultured cells in a cumbersome, time-consuming process. This means that it can be challenging to provide an adequate supply of vaccines in the face of an emerging influenza pandemic. Messenger RNA-whose sequence can be easily altered to match the sequence of a new influenza strain-can be produced by a far simpler and quicker process and could prove a useful alternative.
Lothar Stitz and colleagues tested this theory by vaccinating mice, ferrets and pigs with an mRNA vaccine. They report that the resulting immune responses were similar or superior to those triggered by commercially available vaccines. The mRNA vaccines also possess two other advantages: stability at high temperature and efficacy in very young and very old mice. If this method can be transferred to humans, these features might address additional deficiencies of existing influenza vaccines, namely providing sufficient protection to infants, the elderly and those living in areas lacking refrigeration.