Influenza (flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness. Serious outcomes of flu infection can result in hospitalization or death. Some people, such as older people, young children, and people with certain health conditions, are at high risk of serious flu complications.
People with the flu can spread it to others up to about 6 feet away. Most experts think that the flu viruses spread mainly by droplets made when people with the flu cough, sneeze, or talk. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs. Less often, a person might get flu by touching a surface or object that has the flu virus on it and then touching their own mouth, nose, or possibly their eyes.
People with the flu are most contagious in the first three to four days after their illness begins. Symptoms can begin about 2 days (but can range from 1 to 4 days) after the virus enters the body. That means that you may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick.
The flu is different from a cold. People who are sick with the flu often feel some or all of these symptoms:
- Fever or feeling feverish/chills
- Cough
- Sore throat
- Runny or stuffy nose
- Muscle or body aches
- Headaches
- Fatigue (tiredness)
- Some people may have vomiting and diarrhea, though this is more common in children than adults.
The first and most important step in protecting against the flu is getting your yearly flu shot. More information about the flu shot and the mandatory flu shot requirement for students can be found here.
