Flu Basics
How Flu Spreads
The main way flu viruses spread is from person to person when an infected person coughs, sneezes or talks. When someone with the flu coughs or sneezes, droplets containing the virus are sprayed into the air. Someone else can become infected if they breathe the infected droplets, or touch infected droplets on surfaces and then touch their own eyes, nose or mouth.
Symptoms of Flu
Flu symptoms can often be confused with the common cold, but the flu usually comes on more suddenly and is more severe than the common cold. Symptoms of flu may include fever (usually high), headache, tiredness and weakness (can be extreme), dry cough, sore throat, runny or stuffy nose, body or muscle aches, nausea, vomiting and diarrhea (much more common among children than adults). People with colds are more likely to have a runny or stuffy nose and typically do not develop serious health problems.
A person who is sick with the flu is contagious, meaning they can spread the virus. Adults can be contagious from one day before having symptoms to seven days after getting sick. Children can be contagious for even longer than seven days.
Learn more about the difference between flu and a common cold and how to care for yourself at home when you are sick with the flu.
Preventing the Flu
Getting an annual flu vaccine protects yourself, your family, and the vulnerable people in your community.
Learn more ways to fight the flu.
Complications of Flu and When to Seek Care
In some people, flu can cause serious complications such as bacterial pneumonia, dehydration and heart failure. The people most at risk of complications for seasonal flu are:
- Children younger than 2 years.
- Adults 65 and older.
- People with weakened immune systems and chronic illnesses such as asthma, congestive heart failure and diabetes.
If you have underlying medical conditions you are at greater risk of developing flu-related complications; you should consult your doctor if you have flu symptoms.
When to seek medical care for flu
What you should know about flu antiviral drugs
Other Types of Flu
Flu Information for Health Care Professionals and Laboratories