Facts About Flu

What to know about the flu

Know what causes the flu.

The flu is a contagious illness caused by any of several types of influenza viruses. The virus infects the respiratory system—the nose, throat, and lungs.

There are 4 types of influenza virus: A, B, C, and D. According to the Centers for Disease Control and Prevention (CDC), types A and B are responsible for seasonal flu epidemics.

TYPE A is the most common in adults—and often the most harmful. Subtypes of type A have caused some of the deadliest flu pandemics in history
TYPE B is also contagious and can cause outbreaks of seasonal flu

For more details about the influenza virus, visit the CDC website.

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There are 4 types of influenza virus: A, B, C, and D. According to the Centers for Disease Control and Prevention (CDC), types A and B are responsible for seasonal flu epidemics.

TYPE A is the most common in adults—and often the most harmful. Subtypes of type A have caused some of the deadliest flu pandemics in history
TYPE B is also contagious and can cause outbreaks of seasonal flu

For more details about the influenza virus, visit the CDC website.

Know when flu season starts.

In the United States, flu season starts in the fall and lasts through the winter. Flu activity typically peaks between December and February, but it can last until May.

The CDC monitors flu activity year-round and reports on what viruses are circulating and the incidence of flu-related hospitalizations and deaths. For the most recent information, visit the CDC website.

Know how the flu spreads.

Flu viruses travel through the air in droplets when someone with the infection coughs, sneezes, or talks. You can become infected when you inhale the droplets directly or pick up the germs from touching an object and then touching your eyes, nose, or mouth.

To lower your chance of infection, avoid contact with people who have the flu and wash your hands frequently.

Know how COVID-19 differs from the flu.

Although COVID-19 and the flu may have some symptoms in common, they are 2 distinct illnesses. They are caused by different viruses and require different vaccines—and both can be life threatening. Visit the CDC website to learn more about COVID-19.

Warning signs of a potential flu emergency.

People experiencing any of these warning signs should obtain medical care right away.

Difficulty breathing or shortness of breath
Persistent pain or pressure in the chest or abdomen
Persistent dizziness, confusion, or inability to arouse
Severe weakness or unsteadiness
Fever or cough that improve but then return or worsen

Know how to help protect yourself and your family from the flu.

The flu is a serious illness that can have serious, even deadly, consequences.

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A wolf in sheep's clothing

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Sanofi does not provide medical advice, diagnosis, or treatment. The health information contained herein is provided for general educational purposes only. The best source of information regarding your health is your health care professional, who should be consulted if you have any questions.

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