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Influenza - the flu - is familiar to all of us. It's so common, in fact, that we often forget how serious it can be.
Influenza is an acute viral respiratory infection. It spreads easily from person to person1 including at home, at school, at work and other crowded areas such as at the supermarket or on the train to name a few.

Each year, influenza causes 3 to 5 million cases of severe illness around the world and about 290,000 to 650,000 respiratory deaths1. It is estimated that 10,000 deaths in England and Wales are attributable to influenza infections annually2. In the United States alone influenza results in an estimated:

  • 9.3 - 49

    million illnesses
    estimated annually
    since 2010*

  • 17 million

    lost workdays^

  • 91 million

    lost schooldays~

Seasonal Influenza

CSL Seqirus is on the front line of influenza protection, helping guard against costly and life-threatening epidemics and pandemics. Vaccination is the most effective way to prevent influenza1

More dangerous than you might think

It's estimated that about 1 in 18 children, 1 in 38 elderly and 1 in 45 adults3 who get influenza-like illnesses will seek medical attention, so the disease could be more widespread than we know.

Death from influenza is much more common among the elderly and the very young, but all ages are at risk for serious complications such as pneumonia, myocarditis, and inflammation of the brain or meninges.2

Our bodies and the influenza virus are in a never-ending race. As our immune system evolves to avoid infection, the virus adapts to evade our immune system. This is why we need new influenza vaccines each influenza season - and why we are always working to stay ahead of the mutating virus. The new virus strains generally appear first in Southeast Asia then travel to the rest of the world. Influenza spreads best when temperatures and humidity are low, so the flu season coincides with the winter months in all different parts of the globe. 
Learn more about pandemic influenza

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Our Products

CSL Seqirus is a reliable supplier of seasonal influenza vaccine with the ability to rapidly respond to pandemic threats. CSL Seqirus also in-licenses a wide range of vaccines, antivenoms and pharmaceutical products from our partner licensors to ensure these products are available to meet the needs of Australia's community at home and abroad. You should speak to your healthcare professional for specific advice on influenza vaccination or treatment.

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Report an Adverse Event

To report a suspected side effect or adverse event, please visit our Report an Adverse Event page.

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Pandemic Response Solutions

When it comes to the next influenza pandemic, experts agree it’s not a matter of if, but when. CSL Seqirus partners with governments around the world to prepare for pandemic threats, with our portfolio of pandemic vaccines and our manufacturing facilities ever-ready for rapid response.

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* Centers for Disease Control and Prevention. (n.d.). Disease Burden of Influenza. Retrieved from (Accessed March 2019)
^ Centers for Disease Control and Prevention. (n.d.). Influenza (Flu) in the Workplace. Retrieved from (Accessed March 2019)
~ Walgreens 2013 Flu Impact Report. (2013) Retrieved from (Accessed March 2019)

1. World Health Organization. Influenza (Seasonal) Fact Sheet, January 2018. Available online: (Accessed March 2019)
2. Public Health England. Immunisation against infectious disease: the green book. Chapter 19: Influenza, August 2018. Available online: (Accessed March 2019)
3. Fox, M. (2009, Feb.) Few in U.S. see doctor or get medication for flu: study. Retrieved from: (Accessed March 2019)
4. Centers for Disease Control and Prevention. Seasonal Influenza (flu). Prevent Flu.  (Accessed March 2019).
5. NHS Choices, Flu Vaccine FAQs. Accessed November 2018.
6. NHS, Vaccinations: (Accessed March 2019).
7. Centers for Disease Control and Prevention, How Flu Spreads. Found at (Accessed March 2019)
8. Centers for Disease Control and Prevention, The Flu: What To Do If You Get Sick found at (Accessed March 2019)
9. Centers for Disease Control and Prevention, Flu Symptoms & Complications. Found at (Accessed March 2019)