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Cell-based flu vaccines demonstrate superior effectiveness as CSL builds advanced manufacturing facility in Melbourne

• Cell-based influenza vaccines demonstrated between 10% and 15% relative vaccine effectiveness across three recent seasons compared to traditional egg-based vaccines in the prevention of test-confirmed influenza, according to a new study presented at ESWI Influenza Conference in Spain.1

• CSL Seqirus has welcomed the data as it accelerates towards the end of construction of its new seasonal and pandemic cell-based influenza vaccine manufacturing facility in Tullamarine, Melbourne.


Cell-based influenza vaccines have demonstrated consistently superior effectiveness compared to traditional egg-based vaccines in a new study presented today at the 2023 European Scientific Working Group on Influenza (ESWI) Conference in Spain.1 

Australian vaccines company, CSL Seqirus, has welcomed the data as it prepares for construction completion at its advanced vaccine manufacturing facility in Tullamarine, Melbourne. Seasonal and pandemic cell-based influenza vaccines will be produced at the facility for use in Australia and around the world when it comes online in 2026. 

According to the study, cell-based influenza vaccines demonstrated between 10 – 15% relative improvement in vaccine effectiveness compared to traditional egg-based vaccines in preventing test-confirmed influenza among people aged 4 – 64 years, during three influenza seasons in the United States (2017/18 – 2019/20).1

A recent Australian study showed that if half of the population under 65 years had received flu vaccines with a 15% improved effectiveness between 2015 and 2019, Australia could have prevented up to an additional 12,660 notified flu cases and 1,300 people being hospitalised per year.2

Cell-based influenza vaccines have been available in Australia since 2021 and are a significant innovation in influenza prevention.3 Manufacturing the vaccine using this method eliminates the introduction of mutations that occur during the traditional egg-based manufacturing process and can impact the vaccine.4

Jonah Smith, Vice President and Program Lead for the new CSL Seqirus Manufacturing Facility says the data is important in demonstrating the value of the company’s investment.  

“CSL Seqirus have distributed over 215 million cell-based influenza vaccine doses worldwide, with demand doubling in the last two years. Australia will soon be a major contributor in meeting this demand through our new facility, so it’s important for us to show that these vaccines can help deliver improved outcomes for people and the health system.”   
“This will be the only cell-based seasonal and pandemic influenza vaccine manufacturing facility in the Southern Hemisphere and will provide access to innovative Australian-made vaccines. This technology also offers scale and production time advantages over the traditional influenza vaccine manufacturing process, which is an important consideration for pandemic preparedness.”  

CSL Seqirus’ new $800m facility will bolster Australia’s sovereign manufacturing capability and underpins a long-term partnership between the Australian company and the Federal Government for the supply of seasonal and pandemic influenza vaccines, antivenoms and Q fever vaccine.

Dr Jonathan Anderson, CSL Seqirus Executive Medical Director says the ability to manufacture cell-based vaccines locally could play an important role in protecting public health. 
“Influenza has a huge impact on society – both on people’s lives and the healthcare system.  These incremental improvements in vaccine effectiveness can significantly reduce that impact, especially when implemented on a large scale,” said Dr Anderson.2 

“Being able to produce these kinds of vaccines on Australian soil will mean we can be more prepared to help prevent flu in seasons with higher activity, like 2019, or when traditional vaccines have low effectiveness, like we saw in 2017.2 Now that flu and COVID-19 are co-circulating, that kind of reduced impact on our health system could be critical.”  

Associate Professor Sheena Sullivan, epidemiologist and study author, says real world studies are important for helping improve our understanding of different vaccine technology. 

“Randomised controlled trials are great for diseases that don’t mutate quickly but flu vaccines are updated every year and we can’t run a randomised trial with every update. Trials also often exclude the people most in need of these vaccines.  So, we need different methods of evaluating these vaccines to understand how they work in the real world,” said A/Prof Sullivan. 

“Real world effectiveness studies like this one help us understand how flu vaccines work each season and against different strains of the virus. This study relied on test-confirmed flu cases instead of a diagnosis based on symptoms alone. This helps us understand which study participants contracted the disease so we can get a more specific evaluation of how effective the vaccine is.”1 


Hamish Walsh
0422 424 338 

Stein et al. Abstract accepted for ESWI 2023, September 2023, Valencia, Spain
Stein et al. Abstract accepted for CDIC 2022, June 2022. Sydney, Australia
Flucelvax Product Information
CDC. 2023. Cell-based Flu Vaccines. Available from: 

About CSL Seqirus
CSL Seqirus is part of CSL Limited (ASX: CSL). As one of the largest influenza vaccine providers in the world, CSL Seqirus is a major contributor to the prevention of influenza globally and a transcontinental partner in pandemic preparedness. With state-of-the-art production facilities in the U.S., the U.K. and Australia, and leading R&D capabilities, CSL Seqirus utilizes egg, cell and adjuvant technologies to offer a broad portfolio of differentiated influenza vaccines in more than 20 countries around the world.

In Australia, CSL Seqirus operates the only local manufacturing facility for seasonal and pandemic influenza vaccine, and produces a range of unique medicines in the national interest, including antivenoms and the world’s only human vaccine for Q fever. The company also in-licenses a broad range of paediatric and adult vaccines and specialty pharmaceutical products. 

About CSL
CSL (ASX: CSL; USOTC: CSLLY) is a leading global biotechnology company with a dynamic portfolio of lifesaving medicines, including those that treat haemophilia and immune deficiencies, as well as vaccines to prevent influenza. Since our start in 1916, we have been driven by our promise to save lives using the latest technologies. Today, CSL – including our three businesses, CSL Behring, CSL Seqirus and CSL Vifor – provides lifesaving products to patients in more than 100 countries and employs 30,000 people. Our unique combination of commercial strength, R&D focus and operational excellence enables us to identify, develop and deliver innovations so our patients can live life to the fullest. For inspiring stories about the promise of biotechnology, visit and follow us on

For more information about CSL, visit

Intended Audience
This press release is issued from CSL Seqirus in Melbourne, Victoria and is intended to provide genuine news information to business media. Please be aware that information relating to the approval status and labels of approved Seqirus products may vary from country to country. Please consult your local regulatory authority on the approval status of Seqirus products.

AU-aQc-23-0001. September 2023.