Cell-based Flu Shots Continually Outperform Egg-based Influenza Vaccines

Results from a recent real-world evidence (RWE) study across three consecutive flu seasons in the United States showed that vaccination with cell-based influenza vaccines resulted in lower test-confirmed influenza rates than traditional egg-based vaccines. 

This retrospective test-negative designed study showed the clinical value of cell-based quadrivalent influenza vaccines (QIVc) compared with traditional egg-based quadrivalent influenza vaccines (QIVe) in preventing outpatient test-confirmed influenza. 

The analysis found that QIVc showed a clinical benefit compared to QIVe in the prevention of test-confirmed influenza in the outpatient care setting, with estimated relative vaccine effectiveness (rVEs) (95% CI) of 14.8% (7 – 22) in 2017–-18, 12.5% (4.7 – 19.6) in 2018-–19 and 10% (2.7 – 16.7) in 2019–-20.

"Vaccines remain one of our greatest tools for fighting influenza, a disease that continues to result in substantial morbidity and mortality worldwide," commented Raja Rajaram, Head of Global Medical Strategy, CSL Seqirus, in a press release on September 19, 2023.

"At CSL Seqirus, we are committed to advancing the science of influenza prevention, and these studies show the benefits of innovative vaccine technologies, including cell-based and adjuvanted influenza vaccine technology, on reducing the burden of flu."

The RWE study was conducted over three consecutive influenza seasons characterized by different circulating influenza viruses and degrees of egg adaptation and aligned with previously published QIVc relative effectiveness studies for the same seasons.

This review of real-world data allows for evaluating trends in the effectiveness of QIVc over time and the context of season-over-season changes, given the variability of influenza viruses.

This data complements randomized controlled trial research, assessing influenza vaccine effectiveness continually and providing an ever-growing data set on real-world outcomes.

Influenza is a contagious seasonal respiratory disease that may cause severe illness and life-threatening complications in some people. Influenza can lead to clinical symptoms varying from mild to moderate respiratory illness to severe complications, hospitalization, and, in some cases, death, says the U.S. CDC.

Study: Stein AN et al. Superior Effectiveness of Cell-Based Versus Egg-Based Quadrivalent Influenza Vaccines Against Outpatient Test-Confirmed Influenza Over Three Consecutive Seasons in the U.S. Presented at ESWI 2023.