Influenza (flu) is a contagious respiratory illness that infects the nose, throat and sometimes the lungs. It can cause mild to severe illness, and serious outcomes can sometimes result in hospitalization or even death. On average, about 8% of the U.S. population gets sick with the flu each year.
Flu is caused by influenza viruses Type A and B, which lead to seasonal flu epidemics. Most times, flu virus is spread from person to person when infected people cough, sneeze or talk and tiny droplets land in the nose or mouth of someone nearby. It may be spread before a person knows they are sick, while they are sick, and 5 to 7 days after becoming sick. When exposed, it may take up to 4 days before you are infected.
The flu usually comes on suddenly. Flu symptoms may include:
- Fever (not everyone with flu will have a fever)
- Sore throat
- Runny nose or congestion
- Muscle or body aches
It is easy to confuse signs of the flu with a common cold. But flu symptoms are more severe and may result in serious health problems. Older people, young children, and people with certain health conditions are at a high risk of serious flu complications.
When a person is diagnosed with the flu, their health care provider may prescribe antiviral drugs to lessen the symptoms and length of their condition. Antivirals can also prevent the development of serious flu complications, such as pneumonia, sinus and ear infections, and inflammation of the heart, brain or muscle tissue.
If you have the flu, you should stay home and avoid contact with other people (except to get medical care). Most people will recover in a few days, but the infection may last up to two weeks. After recovery, stay home for at least 24 hours after the fever is gone.
Everyone should get a flu vaccine each year. A yearly flu vaccine is the first and most important step in preventing influenza. The flu vaccine causes antibodies that protect against infection. It is proven to reduce flu-related illnesses and the associated complications.
Vaccination is especially important for people who are at high risk for complications from flu, such as pregnant women, children younger than 5, people with certain chronic medical conditions, and people who live or work in long-term care facilities.
A reminder for parents—children under 8 years old who are getting vaccinated for the first time will need two doses of flu vaccine to be fully protected.
Other preventative measures to reduce your risk of infection include:
- Avoiding close contact with people who are sick
- Stay home when you are sick
- Cover coughs and sneezes
- Wash your hands frequently
- Avoid touching your eyes, nose and mouth
- Practice other healthy habits