What should I know about flu?

Learn more about the flu and the best ways to keep you and your family healthy. Flu is a seasonal viral infection that can cause mild to serious illness. There are steps you can take to prevent the flu.

Table of Contents

What is flu?

Flu is a disease of the body’s breathing (or respiratory) system, including the nose, throat and lungs. Flu is short for “influenza.” Flu is caused by a virus. In New England, the yearly flu season usually begins in the fall and lasts through March. Flu that occurs every winter season is called “seasonal flu.” CDC along with all U.S States and territories conduct routine testing to identify new flu viruses.

What are the symptoms of flu?

The most common symptoms of flu are fever, cough, and sore throat. Symptoms can also include body aches, headache, chills, runny nose and feeling very tired. Some people, especially young children, also have diarrhea and vomiting. Symptoms last from a few days to up to a week or more.

Note: Symptoms of COVID-19 and RSV can be similar to influenza and testing can identify the cause of your illness. To learn more about these viruses, visit this CDC page for more information.

What should I know about the flu vaccine?

Receiving the flu vaccine is one of the most effective ways to prevent getting the flu. Learn about the flu vaccine and find out where you can get a flu vaccine by visiting vaccines.gov/flu or asking your primary care provider or going to a local pharmacy. The flu vaccine helps your body protect against the flu and it is your best protection against the virus. Getting flu vaccine will not give you the flu.

Is flu serious?

Yes, flu can be very serious. Every year in the U.S. seasonal flu causes thousands of hospital admissions and deaths. Some people are at higher risk of serious health problems when they get the flu. This includes pregnant persons, infants, the elderly, and people with medical conditions like asthma, diabetes, heart disease, kidney disease, neurological and neuromuscular conditions, and weakened immune systems.

How does flu spread?

The flu virus is in droplets of saliva and mucus that come out of the nose and mouth of someone who coughs or sneezes. If you are close enough to a person with the flu (3 - 6 feet) when they cough or sneeze, you can breathe in the virus and get sick. Flu symptoms typically start 1 - 4 days (usually 2 days) after a person breathes in the virus.

Flu is spread easily from person to person. The virus can also live for a short time on surfaces or items you touch like tabletops, doorknobs, phones, and toys. After you touch these objects, you can catch the virus when you touch your mouth, nose, or eyes. Adults with flu can spread it from about one day before symptoms appear to about one week after. Children can spread the flu even longer after they get sick.

How is flu treated?

There are drugs available that your doctor may prescribe to treat flu. The drugs work best if started soon after symptoms begin. Your doctor can determine if you need treatment.

People sick with flu should make sure to drink plenty of fluids, get plenty of rest, eat healthy foods, wash their hands often and stay home to avoid spreading the flu to other people. Over the counter pain relievers may help people with the flu feel more comfortable. Children and teens with the flu should never take aspirin, because a rare but serious disease called Reye’s syndrome can occur. Do not give cough or cold medicines to children younger than 4 years of age.

How do I know if I have the flu?

If you have fever with cough or sore throat, you may have the flu. If you think you have the flu, stay home from work and school and avoid contact with others so you do not spread the virus. If you think you might have flu and you need to see your doctor, call ahead and let them know you might have the flu. That way, your doctor’s office can take steps to avoid the spread of flu to others. Your doctor may test you for flu. Flu tests are typically performed by swabbing your nasal passage.

How can I prevent getting the flu and other respiratory infections?

  • Get the flu and COVID vaccines when they are recommended.
  • Wash your hands often with soap and water, or use an alcohol-based hand gel.
  • Cough or sneeze into a tissue or into the inside of your elbow if you don’t have a tissue.  Throw tissues away and wash your hands.  Always wash your hands before touching your eyes, nose or mouth.
  • Use household cleaners to clean things that are touched often, like doorknobs, toys, and phones.
  • Avoid close physical contact with people who are sick.  Try to stay at least 3-6 feet from someone who is sick. 
  • Stay home from work and school if you get sick with symptoms like a fever, sore throat, headache or cough, and avoid contact with others so the illness does not spread.
    • Stay at home until you have been free from fever for at least 24 hours after your last dose of fever-reducing medication (like Tylenol, Advil or Motrin). For most people this will mean staying at home for about 4 days.
  • Test yourself for COVID-19 Because the symptoms of flu and COVID can be similar, take an at-home COVID test. If you test positive, call your doctor about getting treatment. If you have COVID, you should stay home for 5 days and then wear a mask around others for another 5 days.
  • If you are at higher risk of severe disease from flu, call your doctor about getting tested for flu; there are antiviral treatments if you test positive.

Where can I get more information?

What fact sheets are available to print?

Date published: February 21, 2020
Last updated: November 4, 2022

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