The MST Reader: mRNA Vaccines
The MST Reader is a series of guest posts offering overviews of interesting and timely topics that affect our world.
The MST Reader: mRNA Vaccines
Prior to the COVID-19 pandemic, the fastest that a vaccine had ever been produced was the mumps vaccine approved in 1967, and that took four years. Eight or ten years was a more typical timeframe.
But in 2020, the Pfizer-BioNTech and Moderna vaccines were ready in only 10 months. There were many factors that fed into that achievement, from government funding to an accelerated approval process, but a part of that speed was because these vaccines represented a fundamentally new type of vaccine based on mRNA.
The history of vaccines is both long and short. A thousand years ago, the Chinese were inoculating people against smallpox by exposing them to powdered smallpox scabs, but science didn’t start turning out vaccines systematically until the 20th century. Both old and new vaccination practices hinge on the human immune system’s remarkable ability to generate defenses against almost any pathogen, once it has learned to recognize it.
Previous vaccines worked by introducing a weakened or dead version of a virus into a person’s body, causing their immune systems to develop a resistance which was then effective against a live virus. Vaccines using mRNA, however, cause the body to produce proteins that simulate only parts of a virus, which then triggers the same immune response: when the immune system sees the real virus which contains the protein sequence, it attacks.
DNA stands for deoxyribonucleic acid, and is in the form of the famous double helix that most people picture when we think about the building blocks of life. RNA stands for ribonucleic acid, and though the molecule is also like a string or a chain, it’s more like one half of the double helix, a single strand and much shorter. DNA contains the information needed to build an organism, like a blueprint. Messenger RNA takes that information and moves it around, translating the information in the DNA and taking it to ribosomes where it can be built into proteins.
In the case of an mRNA vaccine, mRNA is introduced into the body which causes our own ribosomes to fabricate just the portions of a virus which then trigger an adaptive immune response which can be built up in preparation for a real viral attack. Where an actual virus would hijack a cell’s machinery to make more copies of the virus and do more damage, a carefully crafted strand of mRNA will use a cell to make just selected, recognizable parts of that virus.
Because the mechanism for creating mRNA vaccines has been in development for decades, substituting in the necessary COVID-19-like mRNA was a relatively quick process. Remarkably, the COVID-19 mRNA vaccines are the first large-scale use of this new vaccine technology, and large-scale it has been, with billions of doses produced and more on the way as the race to stop the pandemic worldwide continues.
How mRNA Vaccines Work – Simply Explained