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Seqirus Presents First-of-its-Kind Study on Cell-based Quadrivalent Influenza Vaccine (QIVc) Efficacy in Children ≥2 to <18 Years Old at the European Society for Paediatric Infectious Diseases (ESPID)


Seqirus, a global leader in influenza prevention, today presented absolute efficacy data on the company’s cell-based quadrivalent influenza vaccine (QIVc) from a randomized controlled trial (RCT) which met its primary endpoint in children and adolescents between ≥2 to <18 years of age over three influenza seasons.[1] This study, which was presented at the European Society for Paediatric Infectious Diseases (ESPID) virtual conference, represents the first absolute efficacy study of a cell-based seasonal influenza vaccine in this population.

“Annual influenza vaccination is extremely important,” said Jonathan Edelman, MD, Vice President, Clinical Development at Seqirus and study author. “This study reinforces our commitment to addressing this very serious public health threat by utilizing our advanced influenza vaccine technologies to help protect as many people as possible, including populations such as children between the ages of 2 and 18.”

Standard influenza vaccines are manufactured using the egg-based manufacturing process and may be subjected to egg-adapted changes.[2] QIVc is developed using the cell-based influenza vaccine manufacturing process, an alternative to egg-based manufacturing.

We are pleased to continue to build a strong body of evidence for QIVc across expanded populations,” said Gregg Sylvester, MD, Chief Medical Officer at Seqirus. “Amidst the ongoing COVID-19 pandemic, we are more grounded than ever in our mission to safeguard against seasonal influenza. With over 100 million doses of QIVc distributed globally as of September 2020, we are proud to share this data highlighting the benefit of our cell-based influenza vaccine technology for young children.”[3]

In the U.S., Seqirus operates a state-of-the-art cell-based manufacturing facility located in Holly Springs, North Carolina, purpose-built in partnership with the Biomedical Advanced Research and Development Authority (BARDA) to increase cell-based vaccine manufacturing capacity and combat pandemic influenza threats.[4] Cell-based influenza vaccine technology may potentially offer advantages over the standard influenza manufacturing process, including being more scalable and offering faster production in the event of an influenza pandemic.2

QIVc is marketed in the United States as FLUCELVAX® QUADRIVALENT, and currently licensed for use in people 4 years of age and older.[5] In the United Kingdom and European Union, QIVc is marketed as FLUCELVAX® TETRA▼ and is currently licensed for use in people 9 years of age and older.[6] The results of this study will be used to support applications to national regulatory bodies such as the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for an expanded age indication in children 2 years of age.

Seqirus plans to continue exploring other clinical research associated with FLUCELVAX QIVc. According to the World Health Organization (WHO), the most effective way to prevent influenza is by receiving a seasonal influenza vaccine.[7] In particular, children younger than 5 years of age can be at a high risk of developing serious complications from influenza.7 Since 2010, estimated annual influenza-related hospitalizations among children younger than 5 years of age have ranged from 7,000-26,000 in the U.S.[8] Since the 2004/05 influenza season, annual influenza-related deaths in children younger than 5 years of age range from 37-188 in the U.S.8


About Seasonal Influenza 

Influenza is a common, contagious seasonal respiratory disease that may cause severe illness and life-threatening complications in some people.[9] Influenza can lead to clinical symptoms varying from mild to moderate respiratory illness to severe complications, hospitalization and in some cases, death.9 The CDC recommends annual vaccination for individuals aged 6 months and older, who do not have any contraindications.[10]Because transmission of influenza viruses to others may occur one day before symptoms develop and up to 5 to 7 days after becoming sick, the disease can be easily transmitted to others.9 Preliminary estimates from the CDC report that from October 1, 2019, through April 4, 2020, there were an estimated 410,000 to 740,000 influenza-related hospitalizations in the U.S.[11] Since it takes about two weeks after vaccination for antibodies to develop in the body that help protect against influenza virus infection, it is recommended that people get vaccinated before influenza begins spreading in their community.10 The CDC recommends that people get vaccinated by the end of October.[12] However, getting vaccinated too early (for example, in July or August), can be associated with reduced protection against influenza infection later in the flu season.12


About Seqirus

Seqirus is part of CSL Limited (ASX: CSL). As one of the largest influenza vaccine providers in the world, 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, 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) is a leading global biotechnology company with a dynamic portfolio of life-saving medicines, including those that treat hemophilia 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 two businesses, CSL Behring and Seqirus - provides life-saving products to more than 100 countries and employs more than 27,000 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 more information about CSL Limited, visit


For more information visit and


Intended Audience

This press release is issued from Seqirus USA Inc. 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 Seqirus products may vary from country to country. Please consult your local regulatory authority on the approval status of 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.






What is FLUCELVAX® QUADRIVALENT (Influenza Vaccine)?

FLUCELVAX QUADRIVALENT is a vaccine that helps protect people aged 4 and older from the flu. Vaccination with FLUCELVAX QUADRIVALENT may not protect all people who receive the vaccine.


You should not get FLUCELVAX QUADRIVALENT if you have had a severe allergic reaction to any of the ingredients in the vaccine.

Before receiving FLUCELVAX QUADRIVALENT, tell your healthcare provider about all medical conditions, including if you:

  • have ever had Guillain-Barré syndrome (severe muscle weakness) within six weeks after getting a flu vaccine. The decision to give FLUCELVAX QUADRIVALENT should be made by your healthcare provider, based on careful consideration of the potential benefits and risks.
  • have problems with your immune system or are taking certain medications that suppress your immune system, as these may reduce your immune response to the vaccine
  • have ever fainted when receiving a vaccine


What are the most common side effects of FLUCELVAX QUADRIVALENT?

  • pain, redness, or a raised hardened area or swelling where the vaccine was given
  • headache
  • tiredness
  • muscle aches
  • feeling unwell (malaise)


Additional side effects seen in children include:

  • sleepiness
  • irritability
  • changes in eating habits


These are not all of the possible side effects of FLUCELVAX QUADRIVALENT. You can ask your healthcare provider for more information.


Ask your health care provider for advice about any side effects that concern you. To report SUSPECTED ADVERSE REACTIONS, contact Seqirus USA Inc. at 1‐844‐275‐ 2461 or VAERS at 1‐800‐822‐7967 or


You are also encouraged to report negative side effects of prescription drugs to the FDA. Visit or call 1‐800‐FDA‐1088.


Before receiving this vaccine, please see the full US Prescribing Information for FLUCELVAX QUADRIVALENT. The information provided here does not include all that is known about FLUCELVAX QUADRIVALENT. To learn more, talk with your healthcare provider or pharmacist.


FLUCELVAX® QUADRIVALENT is a registered trademark of Seqirus UK Limited or its affiliates.





Polina Miklush
+1 (908)


[1] Fortanier, A.C., Põder, A., Bravo, L.C., et al. (2020). Efficacy of Cell-Derived Quadrivalent Influenza Vaccine in Prevention of Clinical Influenza in Children 2 to <18 Years of Age: Results of a Randomised Controlled Trial. Presented at the European Society for Paediatric Infectious Diseases (ESPID) virtual conference.

[2] CDC (2020). Cell-Based Flu Vaccines. Retrieved from: Accessed October 2020.

[3] Data on file. Seqirus Inc; 2020.

[4] This project has been funded in whole or in part with Federal funds from the Office of the Assistant Secretary for Preparedness and Response, Biomedical Advanced Research and Development Authority, under contract numbers HHSO100200600012C, HHSO100200700030C, HHSO100200900101C and HHSO100201200003I.

[5] Data on file. Seqirus Inc; 2020.

[6] Data on file. Seqirus Inc; 2020.

[7] World Health Organization (WHO). (2018). Influenza (Seasonal). Retrieved from: . Accessed October 2020.

[8] Centers for Disease Control and Prevention (CDC). (2020). Flu & Young Children. Retrieved from: Accessed October 2020.

[9] CDC. (2019). Key Facts about Influenza (Flu). Retrieved from: Accessed September 2020.

[10] CDC. (2020). Key Facts About Seasonal Flu Vaccine. Retrieved from: Accessed September 2020.

[11] CDC. (2020). 2019-2020 U.S. Flu season: Preliminary burden estimates. Retrieved from: Accessed September 2020.

[12] CDC. (2020). Who Needs a Flu Vaccine and When. Retrieved from: Accessed September 2020.