How does an mRNA vaccine actually work?
Sophisticated mRNA vaccines were never used in humans before, but this new technology was years in the making
In 1980, something incredible happened. Smallpox, a serious infectious disease, was declared eradicated in humans by the World Health Assembly. Once killing three in 10 people who contracted it, smallpox hasn't been seen in humans since 1977 — thanks to a vaccine.
But vaccines can take years to develop and test to ensure they're safe and effective. A made-in-Canada vaccine for ebola was approved in late 2019 by the U.S. Food and Drug Administration 43 years after the virus was first discovered.
So when our world was plunged into the COVID-19 pandemic, scientists knew they had to act fast.
Inside the Great Vaccine Race, a documentary from The Nature of Things, follows teams of scientists around the world who dropped everything to research the novel coronavirus and worked together to create a vaccine in the fight against COVID-19. The key to their lightning-fast vaccine development? Sophisticated mRNA technology.
The right scientists at the right time
In Germany, Drs. Uğur Şahin and Özlem Türeci, founders of BioNTech, knew this was their moment to put their technology to the test. They had been developing mRNA vaccines — originally conceived as personalized cancer treatments — for decades, and their technology allowed for rapid vaccine development.
As news of the novel coronavirus began spreading, they decided to pivot their research and resources into developing an mRNA vaccine for COVID-19. No mRNA vaccine had ever been approved for use in humans before, but they were confident that they could do it.
"Our [original] goal was to develop a medicine which helps a single individual," says Şahin in the documentary. "And it turned out that the same technology can provide medicines for mankind."
How are mRNA vaccines different?
Vaccines do one thing: they train our immune system to fight back. Many of the vaccines we are familiar with contain a weakened component of a live virus or the inactivated virus itself, and our bodies produce antibodies and T cells to protect us in response.
When the real disease tries to infect us, our immune systems recognize the intruder and are prepared to mount a proper defense.
The COVID-19 vaccines developed by companies like BioNTech and Moderna are different. They're messenger RNA, or mRNA, vaccines and are more sophisticated in how they prompt an immune response.
Instead of giving your immune system components of a virus, an mRNA vaccine provides a section of genetic code that acts as a set of instructions — in this case, the instructions for making what's known as a spike protein.
After receiving a COVID-19 vaccine, our cells take these instructions and get to work making the spike protein (harmless on its own). Soon, our immune system recognizes this foreign protein and quickly learns how to destroy it. The "instructions" eventually break down and our cells stop making the protein — but our immune system remembers the intruder.
If and when our cells are exposed to the coronavirus — which is coated in the now-familiar spike protein — our immune system recognizes the intruder and can mount a quick counterattack.
VIDEO: How MRNA vaccines use a more sophisticated method to trigger an immune response
The teams behind today's COVID-19 vaccines were able to create vaccines so quickly because they already had the perfect technology, one they had fine-tuned over decades. All they needed was the right genetic sequence to add to the vaccine formulation to get the ball rolling.
Eradicating disease takes more than just science
Eliminating smallpox didn't happen overnight. It took decades of inoculation programs to vaccinate as many children and adults as possible before it could be declared "gone forever."
A vaccine — however sophisticated — can only be effective against a disease like COVID-19 if it provides immunity to as many people as possible. As more people get vaccinated, we get closer to choking out the disease that has changed our world.
Watch Inside the Great Vaccine Race on The Nature of Things.
