What's the big deal about mRNA vaccines?
The first COVID-19 vaccines to pass phase 3 testing are mRNA vaccines, which represent a whole new form of vaccination. Never previously have mRNA vaccines been licensed for use in any disease, such as the two-dose Pfizer/BioNTech and Moderna vaccines that have now acquired emergency use authorization from the FDA. What makes them so fascinating, and how do they differ from ordinary vaccines?
The mechanism of action of conventional vaccinations
A vaccine's principal objective is to teach the immune system how to recognize a specific infectious pathogen, such as the virus that causes COVID-19. If the immune system has been properly educated, the virus will be aggressively attacked if it ever enters the body.
Viruses have a core of genes consisting of DNA or RNA that is enveloped in a protein coat. To generate the protein coat, the virus's DNA or RNA genes produce messenger RNA (mRNA), which subsequently produces the proteins. A protein of a given structure is made by an mRNA of that structure.
Traditional vaccinations contain weakened viruses, whereas others just use a small portion of the virus's protein covering. In the case of COVID-19, a component known as the spike protein is crucial.
COVID-19 Resource Center for Coronavirus
While the COVID-19 epidemic is still raging in certain parts of the world, it is slowly fading in the United States. There are now three vaccines approved by the FDA, one of which is for children as young as 12 years old. In the real world, the vaccines are nearly as successful as they were in clinical studies. Some preventative measures have been loosened by the CDC, notably for persons who are completely vaccinated and especially when they are outside. Meanwhile, researchers continue to research remedies and monitor virus variations.
Traditional vaccines work: polio and measles are only two examples of deadly diseases that immunizations have helped to control. Vaccines may have done more benefit for humanity as a whole than any other medical breakthrough in history. However, it takes a long time to produce huge amounts of a virus, weaken it, and then extract the key portion.
The first efforts in developing mRNA vaccines
A small group of scientists began investigating if vaccines could be created more easily about 30 years ago. What if you knew the exact structure of the mRNA that produced a vital component of a virus's protein coat, such as the COVID-19 virus's spike protein?
It is relatively simple to produce vast amounts of mRNA in the laboratory. What if you injected the mRNA into someone, and it traveled through the bloodstream, where it was devoured by immune system cells, which then began to produce the spike protein? Would this help to train the immune system?
Overcoming challenges in the development of mRNA vaccines
While the premise may appear straightforward, mRNA vaccines have faced several challenges that have taken decades to overcome. First, scientists discovered how to manipulate mRNA so that it did not trigger harmful immune system reactions. Second, they discovered how to get immune system cells to eat mRNA as it went through the bloodstream. Third, they figured out how to get those cells to produce big amounts of the crucial protein. Finally, they discovered how to shield mRNA from being damaged by substances in our blood by enclosing it in microscopically small capsules.
They also discovered that, in comparison to typical vaccines, mRNA vaccines can actually induce a stronger sort of immunity: they drive the immune system to produce antibodies and immune system killer cells, resulting in a double attack on the virus.
Then along came COVID-19
So, after 30 years of rigorous research, many groups of scientists — including a Pfizer team working with BioNTech in Germany and a small business in Massachusetts called Moderna — were able to push mRNA vaccine technology to the point where it could actually work. The businesses had developed platforms that could theoretically be used to make a vaccine for any infectious disease by simply inputting the appropriate mRNA sequence.
Then there was COVID-19. Within weeks of detecting the virus, Chinese scientists had established the structure of all of its genes, including the genes that produce the spike protein, and had made this information public on the Internet.
Scientists 10,000 kilometers apart began working on the invention of an mRNA vaccination within minutes. They had enough vaccine to test it in animals and then humans in just a few weeks. Regulators in the United Kingdom and the United States certified that an mRNA vaccine for COVID-19 is efficacious and well-tolerated just 11 months after the SARS-CoV-2 virus was discovered, clearing the way for mass vaccination. In the previous four years, no new vaccination had been discovered.
There is no single scientific breakthrough.
Other dangerous agents, such as Ebola, Zika virus, and influenza, are already being investigated with mRNA vaccines. Cancer cells produce proteins that can be targeted by mRNA vaccines; in fact, recent improvement with melanoma has been described. Furthermore, mRNA technology has the potential to create proteins that are absent in illnesses such as cystic fibrosis.
The science behind the mRNA vaccination, like every other innovation, builds on several prior accomplishments, including
- comprehending the structure of DNA and mRNA, as well as how they function together to generate a protein
- developing technique to determine a virus's genomic sequence
- creating a method to create an mRNA that would produce a specific protein
- overcoming all of the barriers that could prevent mRNA injected into a person's arm muscle from reaching immune system cells deep within the body and encouraging those cells to produce the necessary protein
- Leveraging information technology to broadcast knowledge at light speed around the world.
Every one of these previous breakthroughs relied on scientists' resolve to pursue their long-shot ambitions despite widespread skepticism and even scorn, as well as society's readiness to fund their research.
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