A comprehensive global review has found that mRNA vaccines aren't just highly effective at fighting infectious diseases – they are also very safe.
An international team of researchers led by the University of British Columbia (UBC) reviewed data from laboratory studies, clinical trials, and real-world statistics to fully investigate this relatively novel class of vaccine, from design and manufacturing to its long-term performance.
“After billions of doses, we now have an extraordinary amount of scientific evidence,” says lead author Dr. Anna Blakney, assistant professor at UBC’s Michael Smith Laboratories and School of Biomedical Engineering.
“This review affirms that mRNA vaccines are a safe and highly effective platform, supported by rigorous testing and real-world monitoring," she adds. "It provides an evidence-based foundation as this technology continues to expand into new areas of medicine.”
The review organizes disparate studies and datasets into a single, sweeping peer-reviewed analysis. The aim is to make it easier for healthcare providers, the public, and policymakers to find evidence-backed information on emerging mRNA therapies as they move through development and regulation.
The researchers are quick to point out that, like any vaccine, mRNA vaccines can have side effects.
However, serious complications – such as heavily publicized cases of myocarditis – are rare. What's more, promoting such events to counter vaccine efficacy distorts the weight of evidence demonstrating mRNA technology's significant protection against severe illness, hospitalization and death.
The study also found that mRNA vaccines are safe and effective for children, pregnant people and immunocompromised people.
In addition, booster shots were shown to both strengthen and extend the period of protection. The data makes a strong case for the importance of regular vaccinations, as well as the need for the medicines to evolve as new virus strains emerge.
“With any new vaccine or medicine, it is important that we clearly and transparently communicate the safety data and rigorous testing that supports their use,” says co-author Dr. Manish Sadarangani, professor of pediatrics at UBC and director of the Vaccine Evaluation Center at BC Children’s Hospital Research Institute. “This is essential to building public trust, countering misinformation and supporting informed decisions about vaccination.”
Unsurprisingly, the review also addresses vaccine misconceptions – such as mRNA vaccines changing DNA. This is, of course, false; the mRNA is delivered within a lipid (fat) nanoparticle, and provides the immune system with the instruction manual for building a harmless fragment of a virus.
This is particularly important for novel viruses – like COVID-19 – where the adaptive immune system's cells have never encountered these foreign invaders before. Equipping them with the tools to build this fragment essentially trains them to recognize the real thing if infection occurs.
It's these molecular "learnings" that enable mRNA technology to respond quickly to a virus, preventing serious illness.
What's more, both the mRNA instruction and the lipid nanoparticles are then broken down and flushed from the body after they've served their purpose.
Work is well under way to adapt the technology to combat other problematic viruses, such as influenza and RSV. But scientists are also turning to it for potential cancer and autoimmune therapies.
“This is really about what comes next,” says Blakney. “We’re seeing the same platform being applied to cancer treatment and other diseases. Understanding how these vaccines work – and why they’re safe – helps build confidence in the next generation of medicines.”
Vaccine hesitancy is a complex social issue, and numerous researchers have attempted to understand the root cause of it in the UK, the US and Australia, as well as many other countries, particularly following the rollout of COVID-19 shots. (It, of course, existed before COVID-19, and for very valid reasons in some demographics.)
According to the World Health Organization, as one 2021 US-based paper notes, "Vaccine-hesitant individuals are a heterogeneous group who hold varying degrees of indecision about specific vaccines or vaccination in general."
The scientists behind this new review, however, state that it's important not to diminish vaccine hesitancy. Instead, making evidence-based information more accessible is critical.
“People should feel empowered to ask questions about their health and what they put in their bodies,” says Blakney. “Our goal is to provide clear, credible evidence to inform these conversations and decisions.”
The team adds that accessibility also encompasses vaccine affordability, highlighting the need for low- and middle-income countries to invest in mRNA technology.
“mRNA vaccines have already changed how we respond to global health threats,” says Sadarangani. “With sustained innovation, strong safety monitoring and a commitment to equitable access, they can play a major role in preventing disease and improving health.”
The study was published in the journal The Lancet.
Source: University of British Columbia
Fact-checked by Mike McRae
