WHAT IS INFLUENZA?

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. In the United States alone influenza results in an estimated:

9.3 - 45
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 in the USA, 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

Frequently Asked Questions


How can I prevent influenza?
	The most effective way to prevent influenza is to get vaccinated¹ every year. There are additional steps to help protect yourself against influenza:⁴ 1. Avoid close contact. Avoid close contact with people who are sick. When you are sick, keep your distance from others to protect them from getting sick too. 2. Stay home when you are sick. If possible, stay home from work, school, and errands when you are sick. This will help prevent spreading your illness to others. 3. Cover your mouth and nose. Cover your mouth and nose with a tissue when coughing or sneezing. It may prevent those around you from getting sick. 4. Clean your hands. Washing your hands often will help protect you from germs. If soap and water are not available, use an alcohol-based hand rub. 5. Avoid touching your eyes, nose or mouth. Germs are often spread when a person touches something that is contaminated with germs and then touches his or her eyes, nose, or mouth. 6. Practice other good health habits. Clean and disinfect frequently touched surfaces at home, work or school, especially when someone is ill. Get plenty of sleep, be physically active, manage your stress, drink plenty of fluids, and eat nutritious food.
What are the types of influenza vaccines?⁵
	Traditional influenza vaccines protect against three influenza viruses¹; an influenza A (H1N1) virus, an influenza A (H3N2) virus, and an influenza B virus. These are called trivalent vaccines¹. Quadrivalent vaccines are made to protect against these same viruses plus an additional B strain¹. There is also adjuvanted influenza vaccine⁶. Adjuvants work by boosting the immune response and making the vaccine more effective and longer lasting⁶. Speak to your doctor about which vaccine is right for you.
How does an influenza vaccine work?
	About 10 to 14 days after vaccination, your body makes antibodies that help protect you against any similar influenza viruses that may infect you. The protection lasts for about a year, so covers the current influenza season⁵.
I had the influenza vaccine last year, do I need it again?
	Yes. Influenza viruses are constantly changing and vaccines are developed to protect against the predicted strains each year¹.
Will an influenza vaccination give me influenza?
	No. Injectable influenza vaccines are inactivated and do not contain the live virus, so cannot cause influenza².
How does influenza spread?⁷
	Influenza is highly contagious. An otherwise healthy adult may be able to infect other people as early as 1 day before symptoms develop and as long as 5 to 7 days after becoming sick. Children may remain contagious for longer than 7 days. Influenza can be spread to others up to around 6 feet away⁷. It's widely believed that influenza viruses are spread mainly by droplets made when infected people cough, sneeze or talk. The droplets can then land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs. In addition, it is possible to acquire influenza by touching a surface or object with influenza virus on it and then touching your own mouth or nose.
What are the different ways to treat influenza?⁸
	Usually influenza is a mild illness that does not require medical care or antiviral drugs. In most cases, if you develop influenza symptoms, stay at home and avoid contact with other people if possible, except to get medical care. If, however, you have symptoms of influenza and are in a high risk group (including young children, people over 65 years of age or people with chronic medical conditions), or are very sick or worried about your illness, contact your doctor or health care provider.
What are the complications of influenza?⁹
	Most people who get influenza will recover in a few days to less than two weeks. However, some people may develop influenza complications that can result in hospitalization and be potentially life-threatening. For example, influenza-related complications can include pneumonia, bronchitis, sinus infections and ear infections, to name a few. Influenza can worsen certain chronic health problems. For example, people with asthma may experience asthma attacks whilst they have the flu or people with chronic congestive heart failure may experience a worsening of the condition triggered by the flu⁹.

Consumers should contact their health care professional for further advice.

Our Products

CSL Seqirus is a reliable supplier of seasonal influenza vaccine with the ability to rapidly respond to pandemic threats. Our broad range of influenza vaccines help to safeguard people and communities around the world. You should speak to your healthcare professional for specific advice on influenza vaccination.

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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 https://www.cdc.gov/flu/about/disease/burden.htm (Accessed October 2022)

^ Centers for Disease Control and Prevention. (n.d.). Influenza (Flu) in the Workplace. Retrieved fromhttps://www.cdc.gov/niosh/topics/flu/activities.html (Accessed October 2022)

~ Walgreens 2013 Flu Impact Report. (2013) Retrieved from http://www.multivu.com/players/English/62923-walgreens-flu-season2013/links/62923-2013-Flu-Impact-Survey-10-11-13.pdf (Accessed October 2022)}

^{1. World Health Organization. Influenza (Seasonal) Fact Sheet, January 2018. Available online: http://www.who.int/en/news-room/fact-sheets/detail/influenza-(seasonal) (Accessed October 2022)

2. Public Health England. Immunisation against infectious disease: the green book. Chapter 19: Influenza, September 2022. Available online: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/733840/Influenza_green_book_chapter19.pdf (Accessed October 2022)

3. Fox, M. (2009, Feb.) Few in U.S. see doctor or get medication for flu: study. Retrieved from: http://www.reuters.com/article/us-flu-usa/few-in-u-s-see-doctor-or-get-medication-for-flu-study-idUSTRE51863P20090210 (Accessed October 2022)

4. Centers for Disease Control and Prevention. Seasonal Influenza (flu). Prevent Flu. https://www.cdc.gov/flu/prevent/actions-prevent-flu.htm (Accessed September 2022).

5. NHS Choices, Flu Vaccine FAQs. Accessed October 2022. https://www.nhs.uk/conditions/vaccinations/flu-vaccine-questions-answers

6. NHS, Vaccinations: https://www.nhs.uk/conditions/vaccinations/vaccine-ingredients (Accessed October 2022).

7. Centers for Disease Control and Prevention, How Flu Spreads. Found at https://www.cdc.gov/flu/about/disease/spread.htm (Accessed October 2022)

8. Centers for Disease Control and Prevention, The Flu: What To Do If You Get Sick found at https://www.cdc.gov/flu/treatment/takingcare.htm (Accessed October 2022)

9. Centers for Disease Control and Prevention, Flu Symptoms & Complications. Found at https://www.cdc.gov/flu/consumer/symptoms.htm (Accessed October 2022)}

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