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CSL Seqirus Announces Third U.S. Government Award in Relation to Influenza A(H5N8) Candidate Vaccine

• CSL Seqirus will deliver further H5N8 A/Astrakhan antigen to support the U.S. government's pandemic preparedness activities
• This is the third influenza pandemic preparedness award to CSL Seqirus in the last two years, building on a longstanding partnership with BARDA


CSL Seqirus, a business of CSL (ASX: CSL), was selected by 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), to deliver one bulk lot of H5N8 A/Astrakhan antigen to the U.S. government. This acquisition of a bulk lot will increase BARDA’s stockpile of vaccine to support rapid response in an associated influenza pandemic.

For more than a 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, spreading into South America during 2023.2 Widespread avian influenza has also been persistent across Africa, Asia and Europe3 and mammalian spill-over infections have been reported widely too.4 While the likelihood of sustained human-to-human transmission is “low”, according to the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO), there have been reported a small number of human cases of avian influenza A(H5) in the region, including one in the U.S. in April 2022,1 a case in Ecuador in January 20235 and Chile in March 2023.2

“While human cases are rare, sporadic and isolated, consistent detection of bird and mammalian cases demands vigilance,” said Marc Lacey, Executive Director, Pandemic Response Solutions, CSL Seqirus. “Ongoing surveillance and preparedness efforts are critical to minimize the public health risk.”

Under the terms of the agreement, CSL Seqirus will deliver one bulk lot of H5N8 A/Astrakhan antigen to support the U.S. government’s pandemic response readiness. This is the third award CSL Seqirus has received from BARDA related to the ongoing outbreak of HPAI, following the February 2022 award to produce an H5N8 A/Astrakhan virus vaccine seed and subsequent October 2022 announcement of the selection of CSL Seqirus to deliver an H5N8 A/Astrakhan virus vaccine candidate for assessment in a Phase 2 clinical study. 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 and awards in support of BARDA's pandemic preparedness objectives. 

CSL Seqirus used its cell-based influenza vaccine technology, as utilized for FDA-approved AUDENZ™ (Influenza A(H5N1) Monovalent Vaccine, Adjuvanted), to manufacture the H5N8 A/Astrakhan bulk vaccine at the company's Holly Springs, North Carolina, facility, which was built in partnership with BARDA. In 2022, the Holly Springs facility successfully achieved all of BARDA’s criteria required to establish domestic manufacturing capability for innovative cell-based seasonal and pandemic influenza vaccines. CSL Seqirus established and will maintain the required pandemic readiness to deliver 150 million doses of cell-based pandemic influenza vaccine within six months of an influenza pandemic declaration in the U.S.

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
Influenza is a contagious airborne respiratory disease.6,7 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 novel virus in the human population.8 The timing and severity of pandemic influenza is unpredictable, 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.9  Strain-specific pandemic influenza vaccines are manufactured in response to the declaration of a pandemic.10 Pre-pandemic (also called zoonotic) influenza vaccines are developed in the inter-pandemic period to help protect against influenza strains with pandemic potential; these vaccines can be deployed under government instruction to mitigate the risk of an outbreak or provide a first line of defense in advance of a pandemic vaccine if a pandemic were to be declared.10

About Avian Influenza 
Avian influenza is an infectious type of influenza that spreads predominantly among birds.11  Avian influenza viruses do not normally infect humans, however, in rare cases humans have been infected with avian influenza viruses.12  Illness in humans from avian influenza has varied in levels of severity, from no symptoms or mild illness to severe disease and death.12 The spread of avian influenza from one human to another is very rare and typically has only spread to a few people.12

The recent rise in avian influenza among birds has been driven by highly pathogenic avian influenza (HPAI) A(H5N1).1 CSL Seqirus recommends referring to the WHO statement, and CDC, ECDC or national guidance to gauge the levels of concern regarding the high levels of HPAI activity.1,13,14

About CSL Seqirus
CSL Seqirus is part of CSL (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.

For more information about CSL Seqirus, visit

About CSL
CSL (ASX:CSL) (USOTC:CSLLY) is a global biotechnology company with a dynamic portfolio of lifesaving medicines, including those that treat haemophilia and immune deficiencies, vaccines to prevent influenza, and therapies in iron deficiency and nephrology. 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 32,000 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. 


Em Dekonor
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AUDENZ is a trademark of CSL Seqirus.



Centers for Disease Control and Prevention (CDC). (2022). Bird Flu Current Situation Summary. Retrieved from: Accessed July 2023.

World Health Organization (WHO). Influenza at the human-animal interface summary and assessment, 24 April 2023. Retrieved from Accessed July 2023.

World Organization for Animal Health (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 August 2023.

WHO. Technical Report: Highly Pathogenic Avian Influenza A(H5N1) Viruses Ongoing avian influenza outbreaks in animals pose risk to humans. Retrieved from Accessed August 2023.

WHO. Human Infection caused by Avian Influenza A (H5N1) – Chile. Retrieved from: Accessed August 2023.

CDC. (2016). Pandemic Basics. Retrieved from: Accessed August 2023.

CDC. (2022). Key Facts About Influenza (Flu). Retrieved from: Accessed August 2023. 

WHO. (2014). How pandemic influenza emerges. Retrieved from: Accessed August 2023.

WHO. (2017). Pandemic Influenza Risk Management: A WHO guide to inform and harmonize national and international pandemic preparedness and response. Retrieved from:;jsessionid=4421F16879D2F8B96481F8D0C745C7F3?sequence=1. Accessed August 2023.

10 European Medicines Agency (EMA). (2021). Vaccines for pandemic influenza. Retrieved from: Accessed August 2023 

11 CDC. (2023). Avian Flu, Information on bird flu. Retrieved from: Accessed August 2023. 

12 CDC. (2023). Avian Flu, Bird Flu Virus Infections in Humans. Retrieved from: Accessed August 2023.

13 WHO. (2023). Ongoing avian influenza outbreaks in animals pose risk to humans. Retrieved from: Accessed August 2023. 

14 European Centre for Disease Prevention and Control (ECDC). (2023). Avian influenza overview April – June 2023. Retrieved from: Accessed August 2023.