Moderna shines spotlight on new flu vaccine data

Moderna may be facing regulatory uncertainty in the US for its infectious disease vaccine pipeline, but at least its clinical data is hitting the right notes.

Today, the company revealed that its mRNA-based investigational seasonal influenza vaccine, mRNA-1010, showed greater protective efficacy than a licensed flu jab in the phase 3 P304 trial involving adults aged 50 and over.

Moderna said that the result – which showed its shot was around 26.6% more effective than the comparator – sets up regulatory filings both for mRNA-1010 and its combination flu and COVID-19 vaccine mRNA-1083.

In May, Moderna withdrew its US marketing application for the dual shot with an acknowledgement that it would need to wait for efficacy data from the mRNA-1010 study before it could refile for FDA approval.

P304 revealed a strong relative vaccine efficacy (rVE) compared to the standard flu jab across each flu A and B strain included in the formulation and was also consistently better across different age groups, prior flu vaccination status, and risk factors for severe disease.

It's a shot in the arm for Cambridge, Massachusetts-based Moderna as it faces an evolving regulatory environment for vaccines in the US under new Health and Human Services (HHS) Secretary Robert F Kennedy Jr, a well-known vaccine sceptic.

Recent developments have included righter warnings on mRNA-based COVID-19 vaccines, a narrower-than-anticipated label for Moderna's new COVID-19 booster mNexspike, a new clinical trial requirement for new jabs intended for widespread use, and a proposed ban on a vaccine additive that has become a focal point for activists trying to link vaccines to autism.

Meanwhile, Kennedy's mass termination of the CDC vaccines advisory committee and replacement with candidates that are more closely aligned with his own views has raised major concerns about bias creeping into the regulation of US immunisation programmes, with one US lawmaker claiming that the new panel has members with "preconceived bias" against mRNA and other new technologies.

Moderna's chief executive, Stéphane Bancel, is hoping that the increased efficacy of its mRNA vaccine will trump those concerns, saying that the new data is "a significant milestone in our effort to reduce the burden of influenza in older adults," while "the severity of this past flu season underscores the need for more effective vaccines."

According to the CDC, seasonal flu-related hospitalisations and outpatient visits reached a 15-year high during the 2024-2025 season.

"An mRNA-based flu vaccine has the potential advantage to more precisely match circulating strains, support rapid response in a future influenza pandemic, and pave the way for COVID-19 combination vaccines," said Bancel.