Moderna only won U.S. approval for the first mRNA flu vaccine last month. GSK isn’t waiting around. The British drugmaker announced Tuesday that its own mRNA-based seasonal influenza candidate is moving into a late-stage trial, backed by mid-stage data showing stronger immune responses than both standard- and high-dose approved flu shots in younger and older adults alike.
What makes GSK’s approach different
The detail worth paying attention to here isn’t just that GSK is joining the mRNA flu space. It’s how the company is approaching the biology. Most flu vaccines target haemagglutinin, one of the two major surface proteins on the influenza virus. GSK’s candidate targets both haemagglutinin and neuraminidase. That dual-target design, GSK argues, could improve protection and reduce transmission, not just blunt the severity of infection.
If that holds up in a large trial, it matters. Flu remains a serious and chronically underestimated public health burden, responsible for hundreds of thousands of hospitalizations each year in the U.S. alone. Current vaccines work, but imperfectly, and their effectiveness varies considerably season to season depending on how well the selected strains match circulating viruses. A vaccine that also hits neuraminidase could offer a broader and more durable buffer against that mismatch problem.
GSK says this will be the first late-stage trial of an mRNA flu vaccine built around both surface proteins. That’s a meaningful clinical distinction, not just a marketing one.
The competitive context
Moderna’s mFlusiva, approved in August for adults 50 and older, has already established that mRNA flu vaccines can clear regulatory scrutiny. That approval changed the conversation. It demonstrated feasibility. Now the question is whether second-generation candidates can do more, and GSK is positioning itself as an answer to that question.
Still, late-stage trials are where the real work happens. Mid-stage immunogenicity data, even when it looks strong, doesn’t always translate into clinical efficacy at scale. GSK intends to start the trial this month, so meaningful results are likely years away.
Where this fits inside GSK’s broader strategy
The mRNA flu trial is one piece of a larger acceleration effort at GSK. Under CEO Luke Miels, the company has committed to starting more than 20 late-stage studies by the end of 2026. The driver, at least in part, is pressure from approaching patent cliffs that will erode revenue from existing products. Getting new assets into pivotal trials sooner is the logical response.
For clinicians and health system planners, the pipeline signal here is worth tracking. mRNA flu vaccines, if they prove more effective than conventional options, could eventually change procurement decisions, vaccination program design, and the way seasonal flu is managed in high-risk populations. That’s not a near-term shift, but the groundwork is being laid now.
The mRNA platform showed what it could do during the COVID-19 pandemic. Flu is the next serious test of whether that speed and flexibility can be applied to a virus we’ve been chasing, imperfectly, for decades.