What is a messenger RNA-based vaccine like the Pfizer/BioNTech one?

What is a messenger RNA-based vaccine like the Pfizer/BioNTech one?

Dernière modification le 08/01/2021

This is a highly innovative technology which is very different to traditional vaccines. The latter involve injecting the virus into the body, in either attenuated or inactivated form, to stimulate an immune response. The messenger RNA technique, on the other hand, involves sending a message – a bit like a ‘recipe’ to follow – which is then quickly destroyed.

As their name suggests, these vaccines contain RNA, a molecule almost identical to DNA and found in all living beings. RNA is described as “messenger RNA” (mRNA) when its shape temporarily copies that of a fragment of DNA. It transcribes the genetic information of a part of the virus. The mRNA strands injected into the body carry the coronavirus genes responsible for making a protein.

Once injected, the mRNA enters human cells. The genes are “read” by the “cell factories”, which make the protein. Roughly speaking, the body is given a kind of barcode for the coronavirus. The immune system will make the antibodies.

The proteins, produced in large numbers by the cells, are then detected, and this triggers an immune reaction.

In other words, the immune system will make antibodies to destroy the coronavirus. These same antibodies will be able to recognise and effectively fight the coronavirus if it later attempts to infect the body.

Once the RNA has been “read”, it is quickly destroyed and no trace of it is left in the body.

Since this technique prompts a moderate immune response, it requires the administration of two doses, 21 days apart, to ensure lasting protection.