U.S. health officials have approved Moderna's mFLUSIVA, the first influenza vaccine to utilize messenger RNA (mRNA) technology, similar to that used in COVID-19 vaccines. The U.S. Food and Drug Administration (FDA) announced the approval on Wednesday, with the vaccine targeted for adults aged 50 to 64.
The new vaccine is designed to combat rapidly spreading strains of influenza that traditional vaccines, which are approximately 40% effective, often struggle to target. Clinical data suggests mFLUSIVA may be about 27% more effective than conventional flu shots.
The FDA is also considering approval for individuals over 65, a group particularly vulnerable to severe flu symptoms and death due to naturally declining immune systems. This potential approval is contingent on Moderna conducting further trials in this demographic over two flu seasons.
The vaccine is slated for rollout ahead of the upcoming respiratory virus season, which typically runs from September through April. Last year's flu season saw at least 32 million illnesses, 380,000 hospitalizations, and 24,000 deaths in the U.S., with severe outcomes disproportionately affecting young children and older adults.
Moderna's mRNA technology works by instructing the body's cells to produce viral proteins, which then trigger an immune response and establish long-lasting protection. White blood cells identify and attack these proteins, remaining prepared to counter the actual virus upon exposure.
While the new vaccine offers a potential advancement, researchers noted that side effects were reported more frequently compared to older flu vaccines. Approximately two-thirds of trial participants experienced injection site pain, fatigue, and headaches, about double the rate seen with traditional shots. Serious adverse events included one instance of fainting, one case of low blood pressure requiring hospitalization, and one report of pericarditis and myocarditis.
Moderna's mFLUSIVA requires two to three months for manufacturing and distribution. The development of mRNA vaccines allows for a quicker response to emerging flu strains compared to traditional methods that can take months and often rely on fertilized chicken eggs for virus cultivation. This faster production timeline could enable a more agile response to the evolving nature of influenza.
Stéphane Bancel, Moderna's chief executive, stated that mFLUSIVA provides an important new option for seniors, highlighting the ongoing potential of mRNA platforms to address public health challenges through scientific innovation. Ronald G. Nahass, president of the Infectious Disease Society of America, welcomed the approval, emphasizing that vaccination remains a critical tool in preventing severe illness and death from influenza.