Progress is being made in the development of mRNA flu vaccines, which take inspiration from the technology used in COVID-19 vaccines. A recent phase 3 clinical trial conducted by Pfizer revealed that its mRNA flu vaccine significantly outperformed traditional vaccines during the 2022–2023 flu season. Researchers published their findings in the November 20 edition of the New England Journal of Medicine.
The trial involved over 18,000 healthy adults aged 18 to 64 from the United States, South Africa, and the Philippines. It specifically measured the incidence of flu in participants at least 14 days post-vaccination. The results indicated that the mRNA vaccine reduced flu cases by approximately 35 percent compared to the traditional vaccine, suggesting enhanced efficacy in preventing illness during that flu season.
Details of the Trials and Efficacy Rates
The mRNA vaccine developed by Pfizer targets hemagglutinin, a protein that facilitates the entry of the influenza virus into human cells. The vaccine was designed to cover four different flu strains, as recommended annually by a committee of the World Health Organization (WHO).
In a related development, Moderna also announced phase 3 trial results for its mRNA flu vaccine aimed at adults aged 50 and older. This trial showed a relative efficacy of around 27 percent compared to traditional vaccines, with nearly 41,000 participants across 11 countries. Older adults are particularly vulnerable to severe complications from influenza, making effective vaccination crucial for this demographic.
The rapid production capabilities of mRNA vaccines present a valuable advantage. Currently, traditional vaccines require up to six months to manufacture after the WHO announces its recommendations for the upcoming flu season. This timeline poses challenges, particularly if a new flu strain emerges late in the season. For instance, a variant that gained traction during the Southern Hemisphere’s flu season has been dominating flu samples in England and Japan this year, yet it was not included in the Northern Hemisphere’s vaccine due to timing constraints.
The Future of mRNA Vaccines Against Influenza
As the Northern Hemisphere prepares for the upcoming flu season, the emergence of this variant highlights the need for more adaptable vaccine technologies. The mRNA platform allows for a quicker response to changes in circulating flu strains, potentially leading to better match rates for vaccines.
The success of the trials for both Pfizer and Moderna indicates a promising new tool in the fight against influenza. As researchers continue to explore the potential of mRNA technology, the hope is that it will enhance public health responses to flu outbreaks in the future.
