The Pfizer-BioNTech and Moderna vaccines that Canadians are receiving could be just the first in a new wave of vaccination against many diseases — driven by the novel technology used to make the shots, researchers say.
Both the Pfizer-BioNTech and Moderna vaccines are mRNA vaccines, which differ from regular vaccines in terms of how they help your body build immunity against a pathogen. Scientists hope that this new approach could lead to the rapid discovery of many new vaccines.
How mRNA vaccines work
mRNA vaccines are essentially a blueprint for your cells, instructing them to make a specific protein that’s found in the SARS-CoV-2 virus that causes COVID-19. When your cells make that protein, your immune system gets trained to recognize it, building antibodies that will help you fight off COVID-19 should you ever encounter the real deal.
“That’s a very efficient way of introducing the immune system to this protein, to the spike protein, so that when one comes in contact with the real virus, one already has a good immune response — both a T-cell response and an antibody response — to fight it off and prevent infection,” said Scott Halperin, director of the Canadian Centre for Vaccinology and a professor of pediatrics, microbiology and immunology at Dalhousie University.
Coronavirus: The science behind the new Covid-19 mRNA vaccines
What makes the mRNA vaccine technology so potentially useful is that the “instructions” can be easily swapped out, Halperin said.
“Very easily you can change the genetic code, and make a protein from a different virus,” he said.
While researchers will still have to look closely at every virus to identify which protein they should train the immune system to target, once you have that piece, it’s relatively easy to create a new vaccine, he said.
With other vaccines, you have to grow the protein in the lab, then put it into the body, he said. With the mRNA vaccines, you just need to give the body the code, then it will produce the protein itself, which makes vaccine manufacturing much easier.
“One day, if you were making a coronavirus vaccine and a new emerging infection came along, you could just stop making the coronavirus vaccine and be up and running and making the other vaccine within weeks as opposed to a year to build a new factory,” Halperin said.
“So that’s the exciting part, is that this platform has the versatility that you can be ready for other emerging infections that might come along.”
While the technology has been in development for over a decade, the Pfizer-BioNTech and Moderna vaccines are the first approved mRNA vaccines.
But scientists have been working on using it for other diseases. According to a 2018 review in Nature, researchers have been investigating the mRNA platform to see if it can be adapted to fight influenza, Zika virus and rabies, among other diseases.
It’s even being investigated as a way to fight cancer. Alyson Kelvin, a vaccinologist with the Saskatoon-based Vaccine and Infectious Disease Organization, said she is “quite excited” about the potential.
This would be a huge advance, she says, because each person’s cancer is unique, broad treatments don’t always work for everyone.
“So what we can do with a cancer-based vaccine is identify specific signatures that are unique to each person’s tumor or cancer and use that as the basis of the vaccine to teach that person’s immune system what that tumor looks like,” Kelvin said. “So the immune system can target, kill it and remove it.”
mRNA technology could also be used to make a better flu vaccine, she said, by shortening the time it takes to produce them and potentially making the vaccines a better match to whatever flu viruses are circulating. Researchers are even working on a universal flu vaccine, she said, that would work against all influenza viruses.
Influenza is estimated to kill around 250,000 to 650,000 people every year, according to the World Health Organization (WHO). Cancer killed around 10 million people in 2020, the WHO said.
After the COVID-19 pandemic, the mRNA vaccine factories could be put to good use working on other viruses, said Thomas Madden, president and CEO of Acuitas Therapeutics, a Vancouver-based company whose technology is used in the Pfizer-BioNTech vaccine.
“Having the capacity to generate billions of doses a year for COVID-19, once the pandemic is addressed, hopefully then that capacity remains available and can be expanded on for other vaccines,” he said.
“This is very much cutting edge technology that’s been in development for many years, but has now been given the opportunity to demonstrate its clinical value and its clinical importance,” he said.
It remains to be seen how long-lasting the protection offered by mRNA vaccines is, according to Halperin.
“We don’t have any known disadvantages, but we don’t have a lot of information because we haven’t followed those people who receive the vaccine for long periods of time,” he said, noting the need for long-term studies of these vaccines.
Despite these outstanding questions, Halperin remains excited about mRNA vaccines’ potential.
“I think it is a real game-changer,” he said. “Usually science moves very slowly, incrementally, but sometimes during a crisis it has to leap.”
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