Flu vaccines utilizing mRNA technology, similar to that of COVID-19 vaccines, are advancing through clinical trials with promising results. In a phase 3 trial, Pfizer’s mRNA flu vaccine demonstrated a relative efficacy rate approximately 35 percent higher than traditional flu vaccines during the 2022–2023 flu season, according to findings published in the November 20, 2023 edition of the New England Journal of Medicine. This study involved over 18,000 healthy adults aged 18 to 64 from the United States, South Africa, and the Philippines.
The trial aimed to determine whether the mRNA vaccine could reduce the incidence of flu among participants at least 14 days after vaccination. The results indicate that the mRNA vaccine outperformed its traditional counterpart in preventing illness. The mRNA vaccine specifically targeted hemagglutinin, a key protein that facilitates the influenza virus’s entry into human cells. It incorporated versions of this protein from four different flu strains, as recommended by a committee of the World Health Organization (WHO).
In a related development, Moderna announced its phase 3 trial results for its own mRNA flu vaccine, which specifically assessed adults aged 50 and older. This vaccine reported a relative efficacy of approximately 27 percent when compared to traditional flu vaccines, with the study including close to 41,000 participants across 11 countries. Given that individuals aged 65 and older face heightened risks of severe complications from influenza, the introduction of mRNA flu vaccines could serve as a vital addition to public health strategies.
One significant advantage of the mRNA technology is its rapid production turnaround. This ability could allow health authorities more time to adjust vaccine formulations according to the WHO’s recommendations. Currently, traditional vaccines require a production timeline of up to six months following strain selection, which can lead to mismatches if a new variant emerges late in the season. For instance, this year, a variant that gained prominence during the Southern Hemisphere’s flu season is now prevalent in samples from England and Japan. Unfortunately, it appeared too late to be included in the Northern Hemisphere’s vaccination strategy.
As the Northern Hemisphere approaches its flu season, the potential for mRNA vaccines to enhance the effectiveness and adaptability of flu prevention strategies becomes increasingly relevant. With ongoing trials and advancements in vaccine technology, there is hope that these innovations will significantly improve public health responses to influenza in the coming years.
