Scientists say mRNA vaccines could transform flu prevention and cancer treatment, if politics doesn’t get in the way
By Bunmi Yekini
When the flu season’s dominant strain blindsides health authorities, as it does with uncomfortable regularity, the consequences are measured in hospital beds and obituaries. The problem is not ignorance. It is time.
Every year, virologists and epidemiologists gather in late February to make an educated guess about which influenza strains will sweep through populations months later. The manufacturing process, largely dependent on growing virus in chicken eggs, is so slow that the vaccine formulated in early spring must be ready by August or September, a lag that sometimes leaves the public protected against a strain that never quite arrived.
mRNA vaccine technology, researchers say, could break that cycle. And after saving an estimated 14 million lives in the first year of COVID-19 vaccination alone, it is now being positioned for a far broader role, from flu prevention to personalised cancer therapy, even as political headwinds in the United States threaten to slow its advance.
How It Works
Unlike conventional vaccines, which introduce a known quantity of foreign protein directly into the body, mRNA vaccines deliver genetic instructions that prompt the body’s own cells to manufacture that protein. The immune system, encountering what appears to be an infected cell, mounts a swift and powerful response.
“It almost shows your body an infection without having the really dangerous parts of a virus,” Andrew Pekosz, a professor of molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health, told a media briefing this week. The platform, he added, is like switching from a horse and buggy to a Corvette; it does the same fundamental thing, just faster and more effectively.
Speed is not merely a convenience. It is the technology’s defining strategic advantage. Where traditional egg-based flu vaccines require five to six months of manufacturing, mRNA vaccines can be produced in under two months. That compressed timeline means scientists could wait longer into the flu season before committing to a formulation, reducing the mismatch between vaccine and circulating virus that undermines effectiveness in bad years.
“This should lead to vaccines that are better matches for what flu viruses people are actually likely to encounter during the season,” said Gigi Gronvall, a health security expert and professor at Johns Hopkins, speaking at the same briefing.
Egg-based production introduces a further complication that mRNA sidesteps entirely. Growing influenza in eggs can introduce mutations that weaken the vaccine’s match to circulating strains. An mRNA flu vaccine would be built directly from the authentic viral sequence, free of that distortion.
Beyond Infection
Perhaps the most striking frontier is cancer. Current mRNA cancer vaccines are therapeutic rather than preventive: once a tumour develops, physicians could theoretically test it, identify the proteins its cells are displaying, and design a personalised mRNA vaccine to direct the immune system against those specific targets.
“One could really design this kind of personalised medicine relatively quickly,” Pekosz said. The concept remains in early development, but the trajectory is accelerating. Moderna’s chief executive has signalled that cancer therapeutics will be a central pillar of the company’s American market strategy.
Gronvall noted that two existing vaccines already prevent cancer, the hepatitis B vaccine and the HPV vaccine, and argued mRNA platforms could eventually improve upon both, as well as target other cancers now being linked to infectious origins. “The future there is really bright,” she said.
Addressing the Fears
Since their emergency rollout in late 2020, mRNA vaccines have attracted a volume of misinformation unusual even by the standards of public health controversy. False claims, that the vaccines alter DNA, cause cancer, or impair fertility, have proved resistant to correction.
Gronvall addressed them directly. mRNA does not linger in the body, she said, and cannot integrate into DNA. The technology’s foundations were published in 2005 by Katalin Karikó and Drew Weissman, work that earned them the Nobel Prize, meaning it had been in development for years before the public ever heard of it. “They’ve been around for a while,” she said.
The vaccines do carry real, documented side effects. The mRNA platform’s tendency to generate a strong immune response can leave recipients fatigued or achy for a day or two, with localised redness at the injection site. A rare but serious concern, myocarditis, or inflammation of the heart, was documented in a small percentage of young males following COVID-19 vaccination. Pekosz was careful to contextualise the risk: the rate of myocarditis from COVID-19 infection itself was significantly higher than from the vaccine.
Gronvall added a corrective to the opposite anxiety, that the absence of side effects signals a vaccine has not worked. “No pain, no gain does not apply to the human immune system,” she said. Vaccine developers are already working on second and third-generation mRNA platforms designed to reduce reactogenicity without sacrificing efficacy.
A Strategic Miscalculation?
Both researchers expressed concern about the current American policy environment. The National Institutes of Health’s reduced emphasis on infectious disease applications, combined with a leaner FDA operating with diminished staff, threatens to slow progress at a moment when the technology’s potential is clearest.
Gronvall described the cancellation of a U.S. contract for an mRNA vaccine against H5N1 avian influenza as “a strategic mistake.” The virus, she noted, is already endemic in the United States and wreaking damage on the agricultural sector. The technical challenges of making an H5N1 vaccine using eggs, the virus is highly lethal in birds, make mRNA an especially attractive alternative.
NIH director Jay Bhattacharya’s suggestion that public distrust of mRNA justifies investment in older, less efficient technologies drew a pointed response. “His job is to create trust in the proven technologies that will help save lives,” Gronvall said. “Giving Americans a less effective product will not help to do that, especially if people see that mRNA vaccines that are more effective are available elsewhere in the world.”
Pekosz was more measured but equally direct. Other countries, he noted, are pressing ahead. Progress will slow without American support, the NIH’s basic science funding is a global engine, but it will not stop.
The World Is Watching
The COVID-19 pandemic demonstrated both the power of mRNA technology and the inequity of its distribution. Wealthy nations secured supplies; much of the developing world waited. International bodies, including the Coalition for Epidemic Preparedness Innovations, exist precisely to prevent that disparity from repeating.
The urgency is not hypothetical. Infectious diseases, as Gronvall observed, do not respect borders. Most people alive today have lived through multiple pandemics. The next one will not announce itself in advance.
“It’s important to have that infrastructure in place to be ready,” she said.
For now, the infrastructure exists, built on decades of research, validated by the largest mass vaccination campaign in history, and capable, its architects argue, of being made considerably better. Whether the political will to fund and deploy it keeps pace with the science is a question no laboratory can answer.