The United States has approved the world’s first seasonal influenza vaccine using mRNA technology, with pharmaceutical company Moderna announcing that the vaccine has received approval from the US Food and Drug Administration (FDA) for adults aged 50 and older.
The vaccine, called mFluViva, is the first flu shot to use the same messenger RNA (mRNA) technology that was widely used in COVID-19 vaccines.
According to Moderna, the FDA granted full approval for adults aged 50 to 64, while those 65 and above received approval through the agency’s accelerated review pathway.
The approval was based on a late-stage clinical trial involving more than 40,000 participants aged 50 and older.
Trial results showed that during the 2024–2025 respiratory virus season, the new vaccine was about 27% more effective than currently approved standard-dose flu vaccines.
Traditional seasonal flu vaccines generally provide protection ranging from 22% to 56%, depending on the circulating virus strains.
Unlike conventional flu vaccines, which often require months to produce and may involve growing viruses in fertilised chicken eggs, mRNA vaccines can be developed much more quickly.
Scientists believe the faster production process could allow vaccine manufacturers to respond more rapidly to circulating flu strains, potentially enabling countries to select vaccine formulations better suited to local outbreaks rather than relying on a single seasonal formula.
In the clinical trial, around 21,000 participants received Moderna’s vaccine, while a similar number received a standard flu vaccine.
Within six months, 411 people in the Moderna group contracted influenza, compared with 557 people in the comparison group.
However, the study also found that the new vaccine caused more mild side effects than conventional flu shots.
Nearly two-thirds of recipients reported pain at the injection site, while 45% experienced fatigue and 38% reported headaches—roughly twice the rate seen in those who received the standard vaccine.
The mRNA platform gained global recognition during the COVID-19 pandemic, with hundreds of millions of doses administered worldwide. The scientists behind the development of mRNA technology were awarded the 2023 Nobel Prize in Physiology or Medicine for their groundbreaking work.
