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For older Americans preparing for another flu season, the annual vaccination routine comes with a new option. The United States has approved its first mRNA based influenza vaccine, introducing technology that became widely known through Covid 19 vaccines into seasonal flu prevention.
The vaccine, called mFLUSIVA, was approved by the US Food and Drug Administration on August 5 for adults aged 50 and older. The approval covers people aged 50 to 64 through the traditional approval pathway, while its use in adults aged 65 and above was approved through an accelerated process that requires additional studies to confirm clinical benefit.
Unlike conventional flu vaccines, which are generally produced using influenza viruses grown in eggs or cells, mRNA vaccines work by giving the body genetic instructions to produce a viral protein. The immune system then responds to that protein and develops defences against future infection.
The technology could also change how quickly flu vaccines are adapted to circulating strains.
Influenza viruses constantly change, meaning scientists have to predict which strains will dominate months before the flu season begins. Traditional manufacturing adds another challenge because vaccine production takes time.
mRNA technology can be manufactured more rapidly, potentially allowing scientists to select strains closer to the beginning of the season.
Clinical evidence submitted to the FDA showed that mFLUSIVA produced a 26.6% higher relative vaccine efficacy than a standard dose flu vaccine among adults aged 50 and above. The Phase 3 trial involved more than 40,000 participants across 11 countries.
The vaccine also generated stronger immune responses in adults aged 65 and older when compared with a high dose flu vaccine. However, the FDA's accelerated approval means Moderna must conduct further research to establish whether the stronger antibody response translates into a greater clinical benefit.
The vaccine's safety profile was also examined in thousands of participants. The FDA reported that reactions were generally mild to moderate and temporary, with no vaccine related serious safety signal identified in the reviewed studies.
Possible reactions include pain at the injection site, muscle and joint aches, headache, chills, fever, nausea and vomiting.
The arrival of mFLUSIVA is particularly significant for older adults because influenza can cause more serious complications in this age group.
Still, the new vaccine does not replace protection against other respiratory illnesses. Separate vaccines are used for diseases such as Covid 19 and respiratory syncytial virus.
As the flu season approaches, older adults therefore have another option to discuss with healthcare professionals. The development also represents a new chapter in the effort to use mRNA technology beyond Covid 19 and potentially make influenza vaccination more adaptable to a constantly changing virus.
