Leaders in Flu Defense: Insights into the 2024/25 Influenza Vaccine Strategy

Can you provide insights into the decision-making process behind transitioning from quadrivalent to trivalent influenza vaccines for the 2024/25 flu season in the US market? How does this align with the recommendations from the FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) and the WHO’s global influenza response and surveillance system?

CSL Seqirus: A decline in B/Yamagata circulation was detected before the onset of the COVID-19 pandemic by the WHO’s comprehensive surveillance system for tracking influenza virus activity. Subsequently, the WHO confirmed no detected circulation of B/Yamagata lineage viruses since March 2020.

Considerations leading up to the decision to transition to trivalent included the epidemiology and characteristics of the B/Yamagata strain itself. B/Yamagata has shown a slower rate of mutation compared to other influenza virus strains, tends to appear in more temperate climates and had already been in decline before the onset of the COVID-19 pandemic.

In October 2023, the US FDA’s VRBPAC recommended the exclusion of the B/Yamagata strain from quadrivalent influenza vaccines. In February 2024, the WHO made their recommendations for the viral composition of the trivalent influenza vaccines for the 2024/25 flu season in the Northern Hemisphere, reinforcing the exclusion of the B/Yamagata lineage antigen. In March 2024, the VRBPAC met once again and made their recommendations for the strains of A(H1N1) and A(H3N2) as well as the B virus to be included in the 2024/25 Northern Hemisphere trivalent formulation of influenza vaccines licensed for use in the US.

CSL Seqirus is following regulatory body guidance from the FDA and global public health authorities, ensuring that we manufacture vaccines that reflect their clear, market-specific guidelines.

What specific efforts and preparations has CSL Seqirus undertaken to transition its complete portfolio of seasonal influenza vaccines in the US market within the timeline for the upcoming flu season?

CSL Seqirus: CSL Seqirus worked closely with the FDA during 2023 to develop plans and agreed on a path forward, which was finalized in December, to remove the B/Yamagata antigen from the influenza vaccine formulation and convert the full US portfolio. As a result of this effort and our swift response to meet the FDA’s directive, CSL Seqirus received FDA approval on March 4, 2024, for all of its US trivalent influenza vaccines.

As a global leader in the protection of influenza, we proactively communicated the trivalent influenza vaccine strain changes to healthcare providers to support a seamless transition for this upcoming influenza season and that our partners are well-informed. We are working to do our part to help protect communities against influenza and its complications.

From a commercial operations perspective, Dave Ross, as the VP of Commercial Operations (North America), how do you anticipate this transition impacting the market?

Dave Ross: CSL Seqirus is committed to working closely with regulators to ensure a seamless transition and uptake of the trivalent vaccine to mitigate disruption in the market and confusion amongst critical stakeholders.

Timely and fact-based education about influenza vaccination remains essential for all stakeholders (HCPs, consumers, customers) each season. We share concern with the health authorities and healthcare providers we serve about the alarming decline in annual influenza vaccinations, and consistently work with our partners to help reverse these trends to improve public health and alleviate the burden on healthcare systems.

We believe the FDA’s leadership in the trivalent vaccine (TIV) transition will help improve public confidence in influenza vaccines, which in turn may lead to increased uptake of influenza vaccines across the US. The FDA’s actions in this TIV transition are a great example of the important work they do to ensure that all influenza vaccines provided in the US are specifically formulated to the evolving public health need.