The more you understand influenza and its risk to you, the better prepared you'll be to get your flu shot this year.

What is influenza?

The flu, short for influenza, is a highly contagious respiratory infection caused by viruses. The flu can cause mild illnesses for some people. For older people, especially those who have a chronic condition, the flu can be very serious, even life-threatening.

What is influenza a?

Influenza A is the only type known to cause flu pandemics. Influenza A can infect humans as well as animals.

What is influenza b?

Influenza B can cause outbreaks of seasonal flu. This virus spreads among humans, which is different than type A viruses, which can spread between different species (like birds, pigs, and humans).

How long does the flu last?

A bout of the flu typically lasts 5 to 7 days, with severe symptoms subsiding in 2 to 3 days. However, symptoms like weakness and tiredness can linger for more than 2 weeks.

Is the flu contagious?

The flu is easily transmitted from person to person. You can catch the flu when someone who is infected coughs, talks, or sneezes near you. Or you can catch it if you touch a recently contaminated surface or object that has the flu virus on it and then touch your nose, eyes, or mouth.

When is the flu contagious?

Adults are most contagious 24 hours before symptoms start and approximately 5 to 7 days after becoming sick. Children and some people with weakened immune systems can spread the virus for up to a week or longer.

When is flu season?

In the U.S., flu season occurs in the fall and winter. Flu activity typically peaks between December and February, but it can last up until May.

Can someone spread the flu if they don't have symptoms?

People can spread the flu even before symptoms begin. The best way to prevent flu is to get an annual flu shot. It's also good to practice healthy habits year-round, like washing your hands often and covering your nose and mouth when you sneeze or cough.

Can you have flu without a fever?

A fever is part of the immune system's response to an infection and is a common flu symptom. However, not everyone infected with flu will develop a fever. In mild cases of flu, your body may be able to fight off the influenza virus without raising its temperature.

Can you get the flu from the flu shot?

No, you cannot get the flu from the shot. That's because flu shots are either made from pieces of an inactive virus or do not contain virus at all.