New mRNA-based flu vaccines are demonstrating significant efficacy in late-stage clinical trials, potentially offering a major upgrade over traditional influenza shots. These vaccines, built on the same technology that powered successful COVID-19 immunizations, could improve protection against seasonal flu outbreaks.
Pfizer’s mRNA Vaccine Outperforms Traditional Shots
A recent Phase 3 trial published in the New England Journal of Medicine on November 20th shows Pfizer’s mRNA flu vaccine was approximately 35% more effective than conventional flu shots during the 2022–2023 flu season. The study tracked over 18,000 adults across the U.S., South Africa, and the Philippines, measuring the rate of confirmed flu cases at least two weeks post-vaccination.
The mRNA approach targets hemagglutinin, a crucial viral protein used to infect cells. The vaccine includes variants of hemagglutinin from four common flu strains, selected annually by the World Health Organization based on predictive modeling of circulating viruses. This adaptability is one key advantage of mRNA technology.
Moderna’s Vaccine Shows Efficacy in Older Adults
Moderna also announced Phase 3 results in June, with their mRNA flu vaccine showing a 27% relative efficacy over traditional shots in adults aged 50 and above. This trial involved nearly 41,000 participants across 11 countries. This is particularly important, as individuals over 65 face a higher risk of severe flu-related complications.
Why This Matters
Traditional flu vaccines have limitations, including variable effectiveness due to viral mutations and manufacturing delays. mRNA vaccines offer faster development and potentially broader protection. The flexibility of mRNA technology allows for rapid updates to match emerging strains, a critical advantage in an ever-evolving viral landscape.
While these results are promising, wider adoption depends on regulatory approval, manufacturing scale-up, and public acceptance. Further studies will be crucial to assess long-term durability and effectiveness against new flu variants.
