Covid vaccine: what is a messenger RNA?

Published by Laurent P. · Published on 9 December 2020 at 19h01
As Covid vaccine has started to be injected to some people in the world in several countries, many people are wondering what this new technology developed for these products is about, a messenger RNA. Keep reading to find out more!

Messenger RNA in a vaccine, what is it? A question many people are asking as some countries have started to inject the Covid vaccine to some people, as part of different mass-vaccination plans proper to each country. A twenty-year old “technology” used for the first time to create a vaccine for humans and that has many people doubtful, some even say this vaccine might change people’s DNA once they have been vaccinated.

In order to learn more on this technology and what it implies, it is necessary to explain what a messenger RNA is. The messenger RNA (or mRNA) is a modified copy of a DNA strand, used as a code for protein synthesis in the cell. This copy is specifically used as an intermediary to create proteins, they express genes in the human body. In viruses, and especially retrovirus (such as AIDS, for instance), proteins produced by are used, when replicating the virus, as a support for the viral genetic information. This is how it spreads in the human body and makes us fall sick.

A function of the protein the covid vaccine uses to fight against the virus, giving instructions to the human body, via the messenger RNA, to create the same protein, the one found outside the virus (without having it being put within one’s body), and making our immune system react by producing antibodies. “If the vaccine is effective, the organism will learn to recognize this external protein, known as Sars-CoV-2 spicule, and it will generate immune responses as antibodies and cell responseInstitut Pasteur RNA virus evolutive genomic unit head Etienne Simon-Lorière told Franceinfo.

What is the difference between conventional vaccine and mRNA-based vaccine? It is quite simple and easy to sum up: according to France 2 in Complément d'Enquête report: “As the conventional vaccine technique consists in injecting an inactivated (or attenuated) virus for the body to learn how to defend itself, the messenger RNA technique consists in conveying a message to the organism as a piece of DNA. Its goal is to encourage the organism to create an inactive fraction of the virus by itself and the antibodies to fight against this virus”, the journalists explain. In a conventional vaccine, then is injected a modified virus to start an immune response. As for mRNA vaccine, no virus, but only information about it to start the same immune response. A method that – theoretically – makes injecting the vaccine much safer. This is also a way to develop it quicker.

As to know if this mRNA vaccine might change one’s DNA, scientists are formal: it is impossible. As immunologist and head of research at the INSERM Cecil Czerkinsky explained to BFMTV, messenger RNA is “an intermediatory message between the DNA and the protein”, it has no “sequence structure that enables it to mix with genome” and therefore cannot be “included in the host’s (DNA) genome. […] This is one of the advantages of this technology in comparison with DNA-based vaccine, that although more stable, is less effectively translated into RNA then into proteins, and presents a potential theorical risk of being included in the host’s DNA” he concludes.

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