A new real-world data study has found that cell-based influenza vaccines could offer better seasonal flu prevention, showing around 20% greater protection than standard egg-based options during the 2023/24 season. The research, presented at IDWeek 2025, assessed data from over 100,000 vaccinated individuals across multiple age groups and risk categories.
Consistent advantage across populations
CSL Seqirus, the manufacturer behind the study, reported that its cell-based vaccine delivered a consistent advantage in both paediatric and adult populations, regardless of underlying health status. “These data show the clinical benefit of cell-based vaccines over standard egg-based options,” said Dr Gregg Sylvester, Chief Health Officer, CSL Seqirus. “Behind every statistic is a person – we must continue to use real-world evidence as an educational tool.”
Modelling based on the study suggested that universal adoption of cell-based vaccines during the 2023/24 flu season could have prevented nearly 15,000 hospitalisations in individuals under 65, highlighting the potential for significant reductions in healthcare burden. Experts suggest that such outcomes could be particularly valuable in peak flu seasons when hospital systems are under stress.
Shifting landscape in vaccine manufacturing
These findings arrive amid a broader evolution in influenza vaccine technology. While egg-grown vaccines remain the backbone of global supply – employed by most leading manufacturers – companies such as CSL Seqirus and Sanofi are expanding production of cell-based and recombinant platforms. These newer systems help avoid the antigenic drift that can occur when influenza strains adapt to growth in eggs, a challenge long associated with reduced match precision and lower vaccine effectiveness.
Researchers emphasise that this advance is part of a wider trend in biologics manufacturing. “Each flu season brings new evolutionary pressure,” said Dr Sheena Sullivan from Monash University. “Real-world studies like this reveal where we can close that effectiveness gap.”
With global flu vaccination still relying on a diverse portfolio of egg-based, cell-based, and adjuvanted technologies, the landscape is one of coexistence rather than competition. Many experts suggest that this diversification will strengthen supply resilience, reduce the impact of strain mismatches and gradually raise the effectiveness benchmarks for influenza vaccination in future seasons, ultimately improving public health outcomes.
