Flu
The flu, or influenza, is a contagious respiratory infection caused by viruses that can lead to serious complications, particularly in vulnerable populations.
What is the flu?
The flu, also called influenza, is a respiratory infection caused by viruses. Each year, millions of Americans get sick with the flu. Sometimes it causes mild illness, but it can also be serious or even deadly, especially for people over 65, newborn babies, and people with certain chronic illnesses.
What causes the flu?
The flu is caused by flu viruses that spread from person to person. When someone with the flu coughs, sneezes, or talks, they spray tiny droplets that can land in the mouths or noses of people nearby. Less often, a person may get the flu by touching a surface or object that has the virus on it and then touching their own mouth, nose, or eyes.
What are the symptoms of the flu?
Symptoms come on suddenly and may include:
- Fever or feeling feverish/chills
- Cough
- Sore throat
- Runny or stuffy nose
- Muscle or body aches
- Headaches
- Fatigue (tiredness)
Some people, particularly children, may also have vomiting and diarrhea.
Cold vs. Flu
It can be difficult to distinguish between a cold and the flu:
- Start of symptoms: Cold (slowly); Flu (suddenly)
- Fever: Cold (rarely); Flu (usually)
- Aches: Cold (sometimes, slight); Flu (usually)
- Fatigue/weakness: Cold (sometimes); Flu (usually)
- Headache: Cold (rarely); Flu (common)
- Stuffy nose/sneezing/sore throat: Cold (common); Flu (sometimes)
Note: "Stomach flu" is not influenza; it is gastroenteritis.
What other problems can the flu cause?
Complications can be serious or life-threatening, including:
- Bronchitis
- Ear infection
- Sinus infection
- Pneumonia
- Inflammation of the heart (myocarditis), brain (encephalitis), or muscle tissues (myositis, rhabdomyolysis)
The flu can also worsen chronic health problems, such as triggering asthma attacks. Those at higher risk for complications include adults 65 and older, pregnant women, children younger than 5, and people with chronic health conditions like diabetes or heart disease.
How is the flu diagnosed?
Health care providers perform a medical history and ask about symptoms. Diagnosis is confirmed via a swab of the inside of the nose or the back of the throat. Some tests provide results in 15-20 minutes, while others take an hour or more and are generally more accurate.
What are the treatments for the flu?
Most people recover on their own by staying home and avoiding contact with others. If you are in a high-risk group or are very sick, contact your provider. Antiviral medicines can make the illness milder, shorten the duration, and prevent complications. They work best when started within 2 days of getting sick.
Can the flu be prevented?
The best way to prevent the flu is to get a flu vaccine every year. Good health habits, such as covering your cough and washing your hands often, also help stop the spread of germs.