Highlights

  • CSL Seqirus manufactures cell-based influenza vaccines at its Holly Springs facility in North Carolina.
  • Cell-culture production provides an alternative to traditional egg-based influenza vaccine manufacturing.
  • Vaccine formulation, sterile filling and distribution are important parts of the manufacturing process.
  • The company reported opening its Tullamarine cell-based manufacturing facility in FY2026.

CSL Limited (ASX:CSL) is a global biotechnology company with activities spanning plasma-derived medicines, influenza vaccines and other therapies. Its CSL Seqirus division develops and manufactures seasonal and pandemic influenza vaccines using cell-based and egg-based processes. At Holly Springs, North Carolina, the company operates a major cell-based vaccine production site, while its FY2026 annual report also records the opening of a new cell-based manufacturing facility at Tullamarine in Melbourne.

How Cell-Based Production Works

At Holly Springs, CSL Seqirus produces influenza vaccines by growing selected influenza viruses in cultured cells rather than fertilised chicken eggs. The process provides an alternative manufacturing pathway and can reduce reliance on egg supply during periods of elevated vaccine demand. The company describes cell-based production as scalable for both routine seasonal campaigns and potential pandemic response. CSL Limited (ASX:CSL) must nonetheless coordinate production against strain selections, regulatory requirements and seasonal delivery schedules.

Vaccine manufacturing proceeds through cultivation, harvesting, purification and subsequent formulation under controlled conditions. These stages require careful management of biological materials and consistent process controls. Production processes are subject to quality checks, documentation and regulatory review, while output depends on the consistent performance of each manufacturing stage. CSL Limited (ASX:CSL) relies on manufacturing quality systems to support consistent output and product release.

Formulation, Filling and Global Supply

After antigen production, influenza vaccines must be formulated into approved products and packaged for delivery. CSL Seqirus has described expanded formulation and prefilled-syringe filling capabilities at Holly Springs. Sterile handling, batch testing and dependable cold-chain logistics remain important for ensuring that released doses reach vaccination programmes. CSL Limited (ASX:CSL) serves markets across multiple regions, making manufacturing timing and distribution coordination commercially relevant.

The company also uses its MF59 adjuvant technology in certain influenza vaccines. An adjuvant is included to enhance the immune response, particularly where product characteristics and approved indications call for it. Cell-based production and adjuvanted vaccines are distinct parts of the broader CSL Seqirus portfolio rather than interchangeable steps in every vaccine formulation. CSL Limited (ASX:CSL) must match production methods to each authorised product and market.

FY2026 Developments and Operating Challenges

In its FY2026 annual report, CSL reported opening the Tullamarine cell-based vaccine manufacturing facility, extending production capacity and pandemic preparedness capabilities in Australia. The report also described challenging conditions in the US influenza market, while noting progress across differentiated Seqirus products. These developments place the Holly Springs plant within a wider international manufacturing network rather than as an isolated production asset.

Manufacturing risks include contamination, equipment interruptions, changing seasonal demand and the need to align production with influenza strains selected for each season. Regulatory quality standards, product testing and shipment schedules also affect the timing of available supply. For CSL Limited (ASX:CSL), capacity alone does not guarantee commercial outcomes: manufacturing reliability, market demand and the mix of approved vaccines all influence results.

Key Insights

CSL Limited (ASX:CSL) combines cell-based manufacturing at Holly Springs with other production technologies and facilities. Its FY2026 Tullamarine opening adds capacity, while manufacturing execution, product mix, quality controls and vaccine demand remain central factors in the division’s operations.