COVID made mRNA mainstream. WashU says flu shots are next
Washington University researchers say mRNA technology could transform flu shots after proving itself during COVID-19. A Nature Immunology study found Moderna's investigational vaccine triggered stronger, longer-lasting immune responses than traditional shots. On June 18, an FDA panel unanimously backed the vaccine for adults 50 and older, with a final decision due by August 5, 2026.
Key Takeaways
- WashU scientists found mRNA flu shots may produce broader, longer-lasting immunity than conventional egg-based vaccines.
- The FDA's VRBPAC voted 9-0 on June 18 to recommend Moderna's mRNA-1010, branded mFlusiva, for adults 50+.
- Clinical data showed about 27% fewer influenza cases versus standard-dose comparators over a median 181-day follow-up.
- mRNA production could allow faster strain updates when circulating flu viruses shift mid-season.
- Financial disclosures show President Trump purchased Moderna shares in March, weeks before the advisory vote.
Why are flu shots the next mRNA frontier?
COVID-19 made mRNA vaccines mainstream, yet the only mRNA immunizations on the market today remain COVID shots. Influenza is a natural next target because the virus mutates constantly and vaccine makers are consistently playing catch-up to match circulating strains.
Traditional flu shots use weakened or inactive virus. mRNA vaccines instead teach the body to produce antibodies that build immunity. Hanover Matz, a postdoctoral researcher at WashU who worked on the lymph-node study, told STLPR that updating an mRNA-based vaccine when strains change would be much easier than reformulating conventional shots.
That agility matters for a pathogen that never stops evolving. Researchers say influenza is an ideal candidate for the same platform that reshaped pandemic response.
What did Washington University researchers find?
Scientists at Washington University examined how Moderna's investigational mRNA flu vaccine activated immune cells compared with a traditional flu shot. Their work, published in Nature Immunology, is part of a broader research effort into mRNA influenza immunizations.
The team studied contents of patients' lymph nodes. Germinal centers, where infection-fighting immune cells mature, appeared in five of 13 people who received the mRNA vaccine. None of the 15 participants given the traditional flu shot showed that response.
The study also indicated the mRNA vaccine's immune response may last longer and protect against more flu strains.
How did the FDA advisory panel vote?
On June 18, the FDA's Vaccines and Related Biological Products Advisory Committee voted unanimously that the benefits of mRNA-1010 outweigh its risks for adults aged 50 through 64 and for those 65 and older. Contagion Live noted the vote came after the agency had initially refused to review Moderna's application and amid broader federal resistance to mRNA vaccine development.
Across three circulating strains, investigators reported 968 confirmed influenza cases. Illness occurred in 2.0% of mRNA-1010 recipients versus 2.8% of comparator recipients over a median 181-day follow-up, roughly 27% fewer cases. Medically attended influenza outcomes totaled 80 in the mRNA group and 120 in the comparator group.
The FDA has set an August 5, 2026 PDUFA target date for its final approval decision. If cleared, mFlusiva would expand Moderna's commercial respiratory vaccine portfolio at a moment when COVID shots remain the only mRNA vaccines on the U.S. market.
What about Trump's Moderna stock trades?
Separately, newly disclosed financial filings analyzed by Quiver Quantitative show President Donald Trump's accounts purchased Moderna stock on March 2 and again on March 17, 2026, before reporting a partial sale on May 18. The purchases preceded the June 18 unanimous advisory vote.
Moderna shares have gained roughly 49% since the March 2 purchase and about 46% since the March 17 purchase, according to the report. The June panel decision sets the stage for an FDA ruling that could reshape the seasonal flu market.
When could mRNA flu shots reach the public?
Approval before the August 5 deadline could make mRNA flu shots available for the upcoming influenza season.
For more breakthroughs at the intersection of biology and technology, browse our Future Tech & AI Wonders coverage. Read the full STLPR report at STLPR.