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CSL Seqirus Announces U.S. Government Award to Manufacture and Clinically Assess Influenza A(H5N8) Pre-Pandemic Vaccine

• CSL Seqirus will manufacture and clinically assess a cell-based, adjuvanted pre-pandemic influenza vaccine candidate to support the U.S. government’s pandemic preparedness activities
• Third influenza pandemic preparedness award to CSL Seqirus under a multi-year agreement with Biomedical Advanced Research and Development Authority (BARDA)


CSL Seqirus, a global leader in influenza prevention and a business of CSL Limited (ASX:CSL), today announced that the Biomedical Advanced Research and Development Authority (BARDA), part of the Administration for Strategic Preparedness and Response (ASPR) within the U.S. Department of Health and Human Services (HHS), selected CSL Seqirus to deliver an H5N8 A/Astrakhan virus vaccine candidate for assessment in a Phase 2 clinical study that is anticipated to begin in Q2 2023. 

This agreement is the third award that CSL Seqirus has received from BARDA in the last twelve months, following an April 2022 award to produce an H5N8 A/Astrakhan cell-based synthetic influenza Working Seed lot, as well as a separate October 2021 award to develop one influenza A(H2Nx) vaccine virus candidate utilizing its cell-based and adjuvant technologies, and clinically assessing both the cell-based as well as its next-generation self-amplifying mRNA platform, further underscoring the importance of public-private partnerships in bolstering pandemic preparedness. 

Over the past year, outbreaks of highly pathogenic avian influenza (HPAI) A(H5) viruses among wild and farmed birds, as well as commercial poultry, have been reported in the U.S.1 and other parts of North America, as well as across Africa, Asia and Europe.2 BARDA has requested the manufacture and clinical assessment of the H5N8 vaccine candidate to support its pandemic preparedness program.

“Certain influenza strains such as avian flu present a serious pandemic risk, and governments, regulatory agencies, and vaccine manufacturers must take measures to ensure proper and rapid response,” said Dr. Jonathan Edelman, MD, Vice President, Vaccines Clinical Development, Interim Head, CSL R&D Seqirus Vaccines Innovation Unit. “For influenza, this preparation begins with clinical trials to test that a vaccine candidate provides a sufficient level of immunogenicity against the strain of interest, and partnerships with governments guide our decision making as we progress these candidates through the research and development phase.”

Under the terms of the $30.1 million agreement, CSL Seqirus will deliver an H5N8 A/Astrakhan virus vaccine candidate and will then sponsor a subsequent Phase 2 clinical trial to evaluate the candidate along with CSL Seqirus’ proprietary adjuvant MF59®. MF59 has been successfully combined with other influenza strains in vaccines to boost immune response, as well as to accelerate manufacturing output.3 The Phase 2 trial will assess the safety and immunogenicity of this vaccine. Additionally, the study will examine homologous and heterologous boosting after six months, as well as the use of heterologous priming pairs (H5N8 A/Astrakhan and H5N6 A/Guangdong). 

CSL Seqirus will harness its cell-based influenza technology, building on the platform technology used by FDA-approved AUDENZ™ (Influenza A(H5N1) Monovalent Vaccine, Adjuvanted), at the company’s Holly Springs, North Carolina, facility, which was built in partnership with BARDA, to manufacture the required bulk vaccine. The H5N8 vaccine will then be filled into pre-filled syringes (PFS) to support the Phase 2 clinical study. 

“When faced with a public health threat like highly pathogenic avian influenza, governments make plans to protect the population, which takes both time and a substantial collaborative effort with industry,” said Marc Lacey, Executive Director, Pandemic Response Solutions, CSL Seqirus. “For more than a decade, CSL Seqirus has demonstrated its ability to come to the aid of government partners to prepare for and rapidly respond to emerging pathogens of concern, and we are able and ready to do so again for avian influenza.”

CSL Seqirus has been working together with BARDA in a longstanding partnership for more than a decade, which has included numerous R&D and manufacturing activities in support of BARDA’s pandemic preparedness objectives:

  • In 2006, in partnership with BARDA, facilities currently owned by CSL began developing candidate vaccine viruses against different pre-pandemic strains. 
  • In 2013, when a novel influenza H7N9 strain emerged, synthetic seed processes developed in partnership with BARDA were used to initiate the production of CSL Seqirus’ cell-based candidate vaccine. 
  • In October 2021, BARDA selected CSL Seqirus to develop one cell-based influenza vaccine candidate and clinically evaluate two influenza A(H2N3) virus vaccine candidates. 
  • In February 2022, CSL Seqirus was awarded the renewal of a five-year agreement with BARDA to provide pre-pandemic and pandemic goods and services, including influenza vaccines and adjuvants for stockpiling or clinical assessment, to ensure proper preparedness for an influenza pandemic or other public health emergency. 
  • Most recently, in 2022, the Holly Springs facility was recognized by BARDA as having successfully achieved all criteria required to establish domestic manufacturing capability for innovative cell-based seasonal and pandemic influenza vaccines.

This project has been supported in whole or in part with federal funds from the Department of Health and Human Services; Administration for Strategic Preparedness and Response; Biomedical Advanced Research and Development Authority (BARDA), under contract number 75A50122D00004.

About Pandemic Influenza
Pandemic influenza is a contagious airborne respiratory disease which is unpredictable in timing and severity.4 The risk of influenza-associated morbidity and mortality is greater with pandemic influenza than with seasonal influenza because there is likely to be little or no pre-existing immunity to the virus in the human population.5 Four influenza pandemics have occurred over the past century, with the 1918 pandemic being the most severe in recent history, estimated to have killed up to 50 million people worldwide.6 Pre-pandemic influenza vaccines are developed for influenza strains with pandemic potential to provide a first line of defense if a pandemic were to be declared.

About CSL Seqirus
CSL Seqirus is a business 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.

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 Summit, New Jersey, USA and is intended to provide information about our global business. Please be aware that information relating to the approval status and labels of approved CSL Seqirus products may vary from country to country. Please consult your local regulatory authority on the approval status of CSL Seqirus products.

Forward-Looking Statements
This press release may contain forward-looking statements, including statements regarding future results, performance or achievements. These statements involve known and unknown risks, uncertainties and other factors which may cause our actual results, performance or achievements to be materially different from any future results, performances or achievements expressed or implied by the forward- looking statements. These statements reflect our current views with respect to future events and are based on assumptions and subject to risks and uncertainties. Given these uncertainties, you should not place undue reliance on these forward-looking statements.


AUDENZ™ (Influenza A(H5N1) Monovalent Vaccine, Adjuvanted)
Important Safety Information

AUDENZ is an inactivated vaccine indicated for active immunization for the prevention of disease caused by the influenza A virus H5N1 subtype contained in the vaccine.

AUDENZ is approved for use in persons 6 months of age and older at increased risk of exposure to the influenza A virus H5N1 subtype contained in the vaccine.

Do not administer AUDENZ to anyone with a history of a severe allergic reaction (e.g., anaphylaxis) to any component of the vaccine, or after a previous dose of an influenza vaccine.


  • Hypersensitivity reactions can occur. Appropriate medical treatment and supervision must be available to manage possible severe allergic reactions (e.g., anaphylaxis) following the administration of the vaccine. 
  • If Guillain-Barré syndrome has occurred within 6 weeks of receipt of a prior influenza vaccine, the decision to give AUDENZ should be based on careful consideration of potential benefits and risks.
  • Vaccination with AUDENZ may not protect all recipients. Immunocompromised persons, including those receiving immunosuppressive therapy, may have a diminished immune response to AUDENZ.


  • In adults 18 through 64 years of age, the most common (≥ 10%) solicited local and systemic reactions reported in clinical trials were injection site pain (64%), fatigue (25%), headache (25%), malaise (22%), myalgia (14%), arthralgia (10%), and nausea (10%). 
  • In adults 65 years of age and older, the most common (≥ 10%) solicited local and systemic reactions reported in clinical trials were injection site pain (36%), fatigue (20%), malaise (16%), headache (16%), and arthralgia (10%). 
  • In infants and children, 6 months through 5 years of age, the most common (≥ 10%) solicited local and systemic reactions reported in clinical trials were tenderness (56%), irritability (30%), sleepiness (25%), change in eating habits (18%), and fever (16%). 
  • In children 6 through 17 years of age, the most common (≥ 10%) solicited local and systemic reactions reported in clinical trials were injection site pain (68%), myalgia (30%), fatigue (27%), malaise (25%), headache (22%), loss of appetite (14%), nausea (13%), and arthralgia (13%).

To report SUSPECTED ADVERSE REACTIONS, contact Seqirus at 1 855 358 8966 or VAERS at 1 800 822 7967 or

Before administration, please see the full Prescribing Information for AUDENZ.

AUDENZTM and MF59® are trademarks of Seqirus UK Limited or its affiliates. 


Jon Steed
+1 (908) 517-6379

Polina Miklush
+1 (908) 608-7170


Centers for Disease Control and Prevention (CDC). (2022). Bird Flu Current Situation Summary. Retrieved from: Accessed September 2022.

WOAH (2021). The World Organisation for Animal Health (OIE) calls for increased surveillance of avian influenza as outbreaks in poultry and wild birds intensify. Retrieved from: Accessed September 2022.

CDC. (2021). Adjuvanted Flu Vaccines. Retrieved from: Accessed September 2022.

CDC. (2016). Pandemic Basics. Retrieved from: Accessed September 2022.

WHO. (2014). How pandemic influenza emerges. Retrieved from: Accessed September 2022.

WHO. (2017). Pandemic Influenza Risk Management: A WHO guide to inform and harmonize national and international pandemic preparedness and response. Retrieved from: