Seqirus Receives FDA Approval of its Cell-Based Quadrivalent Influenza Vaccine, Expanding the Age Indication to Include Children as Young as Six Months

• Approval aligns with universal age recommendation for all eligible people six months and older to receive annual influenza vaccination¹
• Cell-based influenza vaccines are designed to produce an exact match to the World Health Organization (WHO)-selected influenza virus strains^2,3
• This approval reinforces the value of this innovative influenza vaccine technology as part of Seqirus’ mission to help protect as many eligible people as possible against influenza, especially in light of the ongoing COVID-19 pandemic

Summit, NJ – October 15, 2021

Seqirus, a global leader in influenza prevention, and a business of CSL Limited (ASX: CSL), today announced that the U.S. Food and Drug Administration (FDA) has approved FLUCELVAX^® QUADRIVALENT (Influenza Vaccine), the company’s cell-based quadrivalent influenza vaccine, for an expanded age indication for children as young as six months old.⁴ With this approval, FLUCELVAX QUADRIVALENT, the first and only cell-based influenza vaccine in the U.S., is now indicated for everyone eligible to receive an influenza vaccine in the U.S.⁴

The expanded age indication is supported by a Phase 3 clinical study demonstrating that FLUCELVAX QUADRIVALENT was as safe and immunogenic as a standard quadrivalent seasonal influenza vaccine (QIV) in children six months to <four years of age during the U.S. 2019/20 influenza season.⁵ These data, presented at the Pediatric Academic Society (PAS) virtual Annual Meeting on May 1, 2021, represent the first U.S. Phase 3 study of a cell-based influenza vaccine in this population.

“As one of the world’s largest influenza vaccine manufacturers, we continually seek to apply new technologies and evolve our vaccine portfolio to help address challenges associated with seasonal influenza vaccine effectiveness,” said Dave Ross, Vice President, North America Commercial Operations at Seqirus. “The FLUCELVAX QUADRIVALENT expanded age indication for children as young as six months of age now allows all eligible people to receive a differentiated influenza vaccine option.”

FLUCELVAX QUADRIVALENT utilizes a cell-based influenza vaccine manufacturing process, an alternative to traditional egg-based manufacturing.² Traditional egg-based vaccine production can cause the strain to mutate at several steps throughout the manufacturing process, which may lead to an antigenic mismatch between the circulating strains and the inactivated influenza strains contained within the seasonal influenza vaccine.²

Cell-based influenza vaccines are designed to produce an exact match to WHO-selected influenza virus strains by avoiding egg-adapted changes, and therefore may have the potential for greater vaccine effectiveness.^2,3 Cell-based influenza vaccine technology may offer additional advantages over the standard influenza manufacturing process, including increased scalability and production speed in the event of an influenza pandemic.²

“Throughout our company’s long history as a leader in influenza prevention, we have remained committed to delivering safe and effective vaccines to as many eligible people as possible,” said Gregg Sylvester, MD, Chief Medical Officer at Seqirus. “And while we can never predict how each influenza season will unfold, we could possibly be faced with unique challenges and increased cases this upcoming season as COVID-19 mitigation tactics relax. Therefore, it is critical that all eligible people receive their annual flu vaccine.”

Children younger than five years old, particularly those younger than two, are at increased risk of developing serious influenza-related complications, including pneumonia, brain dysfunction and in rare cases, even death.⁶ Children six months to five years of age who are otherwise healthy are at a high risk of influenza-related complications simply due to their lack of prior immunity.⁷ According to the U.S. Centers for Disease Control and Prevention (CDC), it is estimated that nearly 50,000 hospitalizations occurred in children younger than 18 years of age during the 2019/20 U.S. influenza season, and there were approximately over 486 influenza-related deaths in this age group.⁸ The CDC recommends everyone six months of age and older without contraindications receive an influenza vaccine annually as the best way to prevent influenza.¹

In the U.S., Seqirus operates a state-of-the-art cell-based manufacturing facility in Holly Springs, North Carolina, purpose-built in partnership with the Biomedical Advanced Research and Development Authority (BARDA), a component of the Office of the Assistant Secretary for Preparedness and Response within the U.S. Department of Health and Human Services, to increase cell-based vaccine manufacturing capacity and combat pandemic influenza threats.⁹ Last year, Seqirus announced plans to build a new, world-class cell-based manufacturing facility in Australia, which will be the only cell-based influenza vaccine manufacturing facility in the Southern Hemisphere.¹⁰

About Seasonal Influenza
Influenza is a common, contagious seasonal respiratory disease that may cause severe illness and life- threatening complications in some people.¹¹ Influenza can lead to clinical symptoms varying from mild to moderate respiratory illness to severe complications, hospitalization and in some cases, death.¹¹ 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.¹¹ Estimates from the CDC report that during the 2019/20 influenza season, there were an estimated 380,000 influenza-related hospitalizations in the U.S.⁸ The CDC recommends annual vaccination for individuals aged 6 months and older, who do not have any contraindications.¹ 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.¹The CDC recommends that people get vaccinated by the end of October.¹ Getting vaccinated too early (for example, in July or August), should be avoided, unless there is concern that later vaccination may not be possible, as it can be associated with reduced protection against influenza infection later in the flu season.¹

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 www.csl.com.

For more information visit www.seqirus.com and www.csl.com.

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.

FLUCELVAX^® QUADRIVALENT (Influenza Vaccine) IMPORTANT SAFETY INFORMATION

What is FLUCELVAX^® QUADRIVALENT (Influenza Vaccine)?

FLUCELVAX QUADRIVALENT is a vaccine that helps protect people aged 6 months and older from the flu. Vaccination with FLUCELVAX QUADRIVALENT may not protect all people who receive the vaccine.

Who should not get FLUCELVAX QUADRIVALENT?

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, swelling, or a raised hardened area where the vaccine was given
• headache
• overtiredness with low energy
• muscle aches
• feeling unwell (malaise)

Additional side effects seen in children include:

• tenderness or bruising where vaccine was given
• sleepiness
• irritability
• diarrhea
• 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 and for advice about any side effects that concern you.

To report SUSPECTED ADVERSE REACTIONS, contact Seqirus at 1‑855‑358-8966 or VAERS at 1‐800‐822‐7967 or www.vaers.hhs.gov.
You are also encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch 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 trademark of Seqirus UK Limited or its affiliates.

USA-QIVc-21-0096

MEDIA CONTACT
Maria Tortoreto
+1 (201) 248-5208
[email protected]

REFERENCES
¹ Centers for Disease Control and Prevention (CDC). (2021). Who Needs a Flu Vaccine and When. Retrieved from: https://www.cdc.gov/flu/prevent/vaccinations.htm. Accessed September 2021.

² CDC. (2021). Cell-Based Flu Vaccines. Retrieved from: https://www.cdc.gov/flu/prevent/cell-based.htm. Accessed September 2021.

³ Rajaram, S., Boikos, C., Gelone, et al. (2020). Influenza Vaccines: The Potential Benefits of Cell-Culture Isolation and Manufacturing.

⁴ FLUCELVAX^® QUADRIVALENT (Influenza Vaccine) [package insert]. Holly Springs, NC: Seqirus Inc; 2021.

⁵ Essink, B., Herringa, M., Jeanfreau, R., et al. (2021). Immunogenicity and Safety of Cell-derived Quadrivalent Influenza Vaccine in Children 6 through 47 Months of Age: A Randomized Controlled Non-Inferiority Trial. Presented at Pediatric Academic Societies 2021.

⁶ CDC. (2021). Protect Against Flu: Caregivers of Infants and Young Children. Retrieved from: https://www.cdc.gov/flu/highrisk/infantcare.htm. Accessed September 2021.

⁷ Munoz, F. (2002). The impact of influenza in children. Seminars in Pediatric Infectious Diseases.

⁸ CDC. (2021). Estimated Influenza Illnesses, Medical visits, Hospitalizations, and Deaths in the United States — 2019–2020 Influenza Season. Retrieved from: https://www.cdc.gov/flu/about/burden/2019-2020.html. Accessed September 2021.

⁹ 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 HHSO10020060001F2C, HHSO100200700030C, HHSO100200900101C and HHSO100201200003I.

¹⁰ Data on file. (2020). Seqirus USA Inc.

¹¹ CDC. (2021). Key Facts about Influenza (Flu). Retrieved from: https://www.cdc.gov/flu/about/keyfacts.htm Accessed September 2021.