The flu is a contagious respiratory illness caused by influenza viruses that can cause mild to severe illness, and at times can lead to death. Symptoms of the flu often appear suddenly and can include:

• Fever of 100.4 F or higher
• Aching muscles, especially in your back, arms, and legs
• Chills and sweats
• Headache
• Cough
• Runny or stuffy nose
• Sore throat
• Fatigue and weakness

Stomach symptoms such as nausea, vomiting, or diarrhea may occur but are more common in children than adults. It is important to note that not everyone with the flu will have a fever. Flu symptoms are similar to those caused by COVID-19, making it hard to tell the difference between them based on symptoms alone. Diagnostic testing can help determine if you are sick with flu or COVID-19.

Most people who get the flu will recover in a few days to less than two weeks, but some people will develop complications (such as pneumonia) as a result of flu, some of which can be life-threatening and result in death. Complications from flu among children younger than five can include pneumonia, dehydration, worsening of chronic conditions like asthma, brain dysfunction, and more. If you have emergency symptoms of the flu, get medical care right away.