The same technology that helped protect millions of Canadians during COVID-19 may soon be fighting cancer. A sweeping new review in The Lancet has confirmed what many doctors already believed about mRNA vaccines.
What did researchers find about COVID vaccine effectiveness?
Researchers at the University of British Columbia led one of the most thorough assessments of this technology to date, examining clinical trials and real-world data on the Pfizer-BioNTech and Moderna vaccines from 2020 through 2025.
The findings were clear. COVID vaccine effectiveness came in at 87 percent against documented infection and 94 percent against death within two to six weeks of vaccination. Serious side effects were rare and far less common than the risks of infection itself.
Dr. Manish Sadarangani, a UBC researcher who contributed to the review, told CBC News the goal was to give people a resource to "really understand what we know about this technology" and where it may be going.
Why does this matter for Canadians?
The pandemic gave scientists something they had never had before, an urgent, globally funded reason to scale up mRNA technology and study it across an enormous population. Millions of Canadians received mRNA vaccines, and that experience now sits in the peer-reviewed record.
Canada has seen before what a strong vaccine program can do. A recent study found the HPV vaccine brought cervical cancer deaths to almost zero in young women. And with the federal government moving to share health data with researchers, the evidence base behind technologies like this one is only going to grow.
Can an mRNA cancer vaccine actually work?
That is the question researchers are testing right now. The idea behind an mRNA cancer vaccine is to train the immune system to find and destroy cancer cells after a tumour has been removed. Scientists sequence the mutations in a patient's tumour, identify targets absent from healthy DNA, and deliver a personalized therapy that teaches the immune system to hunt down any lingering cancer cells.
A global clinical trial is currently evaluating this approach for bladder cancer. Dr. Nimira Saleh, a Canadian oncologist involved in the trial, told CBC News that if the immune system learns to recognize cancer cells, the chances of relapse go down and the chances of a cure go up.
The technology is not approved for cancer treatment and remains in early trial stages. But the fact that it is being tested at all reflects how far mRNA science has travelled since 2020.
Frequently Asked Questions
How effective are mRNA vaccines against COVID-19?
The Lancet review found mRNA vaccines were 87 percent effective against documented COVID-19 infection and 94 percent effective against death in the weeks following vaccination. Effectiveness can shift as new variants emerge, which is why health authorities continue to recommend updated booster doses.
Are vaccine side effects from mRNA shots serious?
Serious vaccine side effects are rare. The review found risks such as myocarditis were small, and consistently less common and less severe than the complications caused by a COVID-19 infection itself. Anyone with concerns about their individual risk should speak with a doctor or pharmacist.
Is there an approved mRNA vaccine for cancer?
Not yet. Cancer applications are in early clinical trials, including a global trial for bladder cancer. If those trials succeed, approval would still be years away. What exists today is a promising approach built on the safety record established during the pandemic.
If you have questions about your vaccine history or booster eligibility, a family doctor or walk-in clinic provider is a good first step. Find a clinic and book in minutes, or browse more Canadian health coverage on the Medimap Health Hub.
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