A NEW mRNA-based flu vaccine developed by Pfizer has been found to be 34.5% more effective against influenza-like illness compared to current flu vaccines, according to a new trial published in the New England Journal of Medicine.
The study included over 18,000 healthy adults in the US, South Africa and the Philippines, of whom half were given the mRNA flu vaccine and half a conventional one.
Only 0.63% of people injected with the mRNA flu vaccine came down with the flu, compared with 0.95% of people injected with the conventional flu vaccine, thereby demonstrating a relative vaccine efficacy of 34.5% for the mRNA vaccine.
This improved protection was almost entirely driven by strong results against influenza A viruses (H3N2 and H1N1), which are often responsible for more severe seasonal outbreaks, with a weaker antibody response against influenza B strains.
There were more side effects in the mRNA vaccine group, including pain, fatigue, and headache with fever, although the rates of severe and life-threatening side effects were low and similar in the two trial groups.
There was too little influenza B circulating during the trial to measure real-world effectiveness.
One potential benefit is that manufacturing mRNA vaccines is significantly faster than traditional methods, which rely on growing the virus in eggs or cells, a process that can take six months or more.
Faster production means vaccine strains can be selected closer to the flu season, reducing the risk of mismatch with circulating viruses.
Professor Archa Fox from the University of Western Australia commented that the findings "should help make a case for rolling out mRNA flu vaccines".
"Currently, the only mRNA vaccines in Australia are for COVID-19," she pointed out.
Professor Fox also noted the higher rate of side effects, suggesting the mRNA vaccines seem to trigger a strong immune response.
"This matches another study this year that showed giving an mRNA vaccine in the 30 days before certain types of cancer treatment helps cancer patients' immune system tackle their disease," she added, referring to research on patients with advanced lung or skin cancer (PD 28 Oct).
Associate Professor Vinod Balasubramaniam from Monash University Malaysia highlighted some of the limitations of the study.
"We only know it's better than an existing vaccine, not its exact standalone efficacy; the trial was limited to one season and excluded vulnerable groups like children and the immunocompromised; and most crucially, it showed no significant benefit for adults over 65, the group most at risk from severe flu," he explained.
"This is a promising step forward but not a complete solution for all."
Read the study HERE. KB
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