Cell-Based Flu Shots Found Superior to Egg-Based

While many influenza vaccines are produced in hens' eggs, cell-based quadrivalent influenza vaccines may deliver more protection against seasonal flu.

A recently published study in Nature's Infectious Diseases & Therapy demonstrates that cell-based influenza vaccines offer up to 20% greater relative vaccine effectiveness (rVE) in the prevention of test-confirmed influenza than standard egg-based vaccines.

Key findings from the Real-World Evidence (RWE) study showed greater protection of cell-based influenza vaccines compared to standard egg-based influenza vaccines in the prevention of test-confirmed influenza, with an estimated rVE of 19.8% (95% CI: 15.7 – 23.8%) for the full population.

Consistent rVE results were also observed for the pediatric, adult, outpatient, and high-risk subgroups.

These findings will be presented at the IDWeek 2025 conference, which will take place from October 19 to 22, 2025.

This latest RWE represents the fifth consecutive season of extensive retrospective test-negative studies showing greater protection from cell-based influenza vaccines compared to standard egg-based influenza vaccines.

It offers the first demonstration of superiority in pediatric populations from 6 months of age.

Since vaccine effectiveness is impacted when people get their annual flu shot, as of the end of September 2025, the U.S. CDC stated that most of the United States was not reporting influenza outbreaks.

The CDC says most pharmacies in the USA offer various flu shot services.